- added support for Intel/Marvel PXA27x (XScale) targets

- added support for scans coming from or ending in Shift-DR or Shift-IR to bitbang code (required for XScale debugging)
- cleaned up errror handlers. only use when there's a catchable error
- fix segfault when etm was configured without a valid driver



git-svn-id: svn://svn.berlios.de/openocd/trunk@176 b42882b7-edfa-0310-969c-e2dbd0fdcd60