cons: Simplify buffer management slightly in r_cons_printf

there is no need to check twice if the buffer is full.

In additition the first check (deleted) has an off by one error.
Fix project saves where old data was left at the end if project has shrunk in size
Fix overflow in r_asm_disassemble() and implement rip-relative refs in anal.x86.cs
Merge branch 'master' of github.com:radare/radare2 into project_save_meta