added target->type->examine(). Eventually this will allow for bringing up telnet/gdb *before* jtag chain has been validated + it might fix some reset halt problems seen as examine() needs to run after TRST has been asserted.

git-svn-id: svn://svn.berlios.de/openocd/trunk@563 b42882b7-edfa-0310-969c-e2dbd0fdcd60