Create FAT boot sector.md

Information about the FAT filesystem bootsector
Update TR3200.md

Added missing information about the extra cycle if an instruction uses a big immediate value.
Removed the extra cycle rule if LOAD/STORE is unaligned. This probably will return in an enforce rule, were the two LSB bits are ignored
Removed calling convention file, and FAT stuff.

Added a RFC directory with an RFC for two calling conventions
Add new branch instructions and change opcode

On request of issue #29, the branch instuctions are moved to opcodes 0x70-0x7F.
On request of issue #32, is added IF Great branch isntructions do ">" and ">=" comparations
Fixed opcodes fro branch instructions and updated cheatsheet

Also, updated the CPU version. Branch instructions are opcodes of range 0x70-0x7F
Merge pull request #34 from trillek-team/branch_instructions

Tweaked Branch instructions
Merge branch 'master' of github.com:trillek-team/trillek-computer into gh-pages