What is claimed is:1. An electrochemical cell for the electrolytic removal of at least one metal from solution, the cell including an outer casing, a cathode assembly centrally disposed within the outer casing, an anode within the outer casing spaced from the cathode, an inlet and an outlet for the solution, wherein the cathode assembly comprises a porous elongate support member having a circumferential periphery of characteristic circumferential dimension, a porous cathode member formed of a porous carbon fiber material disposed about the elongate support member, and a cathode current feeder supported on the elongate support member and extending substantially along the entire length of the porous cathode member, the cathode assembly, inlet and outlet being disposed such that in use the solution enters the cell through the inlet, flows through the porous cathode member and exits the cell through the outlet, said cell being characterized in thatsaid cathode current feeder comprises a plurality of feeder strips, each extending substantially the length of said porous cathode member, said plurality of feeder strips being disposed substantially evenly about said circumferential periphery of said elongate support member, wherein each said feeder strip has a characteristic width and the aggregate total of said characteristic widths comprises at least 20 percent of said characteristic circumferential dimension.2. The apparatus of claim 1 further characterized in that said elongate support member has a generally tubular shape, and said feeder strips are substantially flat and are disposed tangentially along their characteristic widths to said circumferential periphery of said tubular shape.3. The apparatus of claim 2 further comprising a generally tubular porous sheath about said porous cathode member, said apparatus being further characterized in that said sheath is formed of an elastomeric material and is sized to squeeze said porous cathode member into electrical contact with said feeder strips.4. The apparatus of claim 1 further characterized in that said elongate support member has a generally tubular shape, and said feeder strips are shaped and disposed along their characteristic widths generally to conform to the curvature of said circumferential periphery of said tubular shape.5. The apparatus of claim 4 further comprising a generally tubular porous sheath about said porous cathode member, said apparatus being further characterized in that said sheath is formed of an elastomeric material and is sized to squeeze said porous cathode member into electrical contact with said feeder strips.6. The apparatus of claim 1 further characterized in thatsaid cathode assembly further comprises an end piece disposed at an end of said support member and formed to restrain said cathode member on said support member;said plurality of feeder strips being releasably secured to said end piece at first ends of said feeder strips; andsaid end piece being arranged to be maintained in position on said support member by said releasably secured feeder strips;whereby said end piece may be easily released and removed from said support member thereby enabling easy removal of a spent said cathode member.7. The apparatus of claim 1 wherein said outer casing is of a generally tubular shape having first and second end caps at the ends thereof wherein said inlet is disposed in said first end cap, said apparatus being further characterized in thatsaid first end cap includes a first removable modular insert defining said inlet and formed to establish flow connection with said cathode assembly, whereby a user may adapt the apparatus for a different flow requirement by replacing said first removable modular insert with a like removable modular insert defining an inlet of different size and without having to remove or replace said cathode assembly.8. The apparatus of claim 7 wherein said outlet is disposed in said second end cap and said apparatus is further characterized in that said second end cap includes a second removable modular insert defining said outlet, whereby a user may further adapt the apparatus for a different flow rate by replacing said second removable modular insert with a like removable modular insert defining an outlet of different size.9. The apparatus of claim 7 further comprising at least one anode current feeder extending through said second end cap, wherein said apparatus is further characterized in that said anode is adapted for connection to said at least one anode current feeder at opposite ends of said anode, said at least one anode current feeder is selectively attachable to and detachable from said anode at said opposite ends, and said first end cap is formed with alternate openings for receiving said at least one anode current feeder, whereby the apparatus may be selectively configured for electrical connection to said anode at either of said first and second end caps.10. The apparatus of claim 1 wherein said outer casing and said anode are of generally tubular shape and are concentric with one another, said apparatus being further characterized in that said anode is spaced apart from the inner wall of said outer casing by a distance of at least 2.5 mm.11. The apparatus of claim 1 further comprising a microporous divider assembly disposed between said cathode assembly and said anode so as to define separate anolyte and catholyte chambers, said apparatus being further characterized in that said divider assembly comprises a microporous membrane, and inner and outer porous supporting sleeves, said microporous membrane being sandwiched between said supporting sleeves.12. The apparatus of claim 11 wherein said inner and outer porous supporting sleeves are of generally concentric tubular mesh shape pressing said microporous membrane therebetween.