Make the BUFF pin a mask like VCC to allow multiple pins to be
asserted at the same time (STK200 has two buffer enable lines).
Add the STK200 programmer.
Fix EEPROM address line selection for several parts.
git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@109 81a1dc3b-b13d-400b-aceb-764788c761c2