Revive tclapi.c from r1650:
* Remove superfluous #include directives.
* Fix warnings and API usage to cure its bit rot.
* Build into libhelper library (for now).
Add tclapi.h to export tclapi_register_commands().
Register tclapi commands in openocd.c:setup_command_handler().



git-svn-id: svn://svn.berlios.de/openocd/trunk@1691 b42882b7-edfa-0310-969c-e2dbd0fdcd60