Working on the new backend. Moved the files from the b6502 into the main

Working on the new backend. Moved the files from the b6502 into the main
compiler dir because the backend is not really a submodule, so this did
not reflect the real relations of the backend to the rest of the compiler.

git-svn-id: svn://svn.cc65.org/cc65/trunk@713 b7a2c559-68d2-44c3-8de9-860c34a00d81