- single core context used, removed debug context as thought unnecessary.

- DCRDR now used to access special core registers - info is currently omitted from the cortex_m3 TRM ARM have told me this is the preferred access method and the docs will be updated soon.
- now checks for User Thread Mode and Thread mode when halted.
- removed repeated function declarations from command.c
- cortex_m3_prepare_reset_halt removed, updated cortex_m3_assert_reset to suit

git-svn-id: svn://svn.berlios.de/openocd/trunk@558 b42882b7-edfa-0310-969c-e2dbd0fdcd60