Adds two "minidriver_imp.h" files, so the right one is allowed to be "#included" by the Makefile logic.
Moves JTAG interface drivers to src/jtag/drivers/, Adds src/jtag/drivers/Makefile.am. Builds libocdjtagdrivers.la. Flattens the rlink driver files into the drivers/ directory, adding the 'rlink_' prefix or '.rlink' suffix as appropriate.