* avrftdi.c, avrftdi_private.h: added additional pin check and bitbanging fallback
* pindefs.[ch]: added a flag to enable/disable output
* ft245r.c: changes because of added flag above
git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk@1184 81a1dc3b-b13d-400b-aceb-764788c761c2