Add header file for JTAG minidriver:

Add header file for JTAG minidriver:
- Wraps all minidriver API functions using API front-ends:
  - Outlines jtag_add_dr_out() and jtag_alloc_in_value32().
  - Adds interface_ prefix to existing jtag_alloc_invalue_32 routines.
  - Re-inline these interface definitions in new header file.
- Re-inline parts of the (mini)driver implementations in minidriver.h.
- Replace INCLUDE_JTAG_MINIDRIVER_H with #include directives.

The next patch will finish removing '#ifdef HAVE_JTAG_MINIDRIVER_H'
from jtag.h.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2006 b42882b7-edfa-0310-969c-e2dbd0fdcd60