Updating the mighty-1284p core

Optiboot 6.0 "alpha": optiboot-6.zip - Google Drive

The important change WRT 1284 is EEPROM support! Also, I think I fixed "Bobuino", and put the 1284/644 in there own sub-makefike, so that adding platforms can be more easily "logically separate" from actual logic changes.

/* 6.0 WestfW: modularize memory read/write functions	  */
/*             Remove serial/flash overlap		  */
/*              (and all references to NRWWSTART/etc)	  */
/*             Correctly handle pagesize > 255bytes       */
/*             Add EEPROM support in BIGBOOT (1284)       */
/*             EEPROM write on small chips now causes err */
/*             Split Makefile into smaller pieces         */
/*             Add Wicked devices Wildfire		  */
/*	       Remove LUDICOUS_SPEED option		  */