Updated Rev C schematic/BOM

With the recent release of the ZedBoard Errata, I have updated the Rev C schematics/BOM.  Note that no functional changes have been made.  The schematics were updated with notes in the areas related to the errata.  The BOM was updated to include the heatsink that now ships with ZedBoard.  That heatsink is also available for purchase on the Accessories page http://www.zedboard.org/accessories.