feature(radare2): add r2pipe command to execute stateful radare2 cmds
feature(radare2): add r2pipe command to execute stateful radare2 cmds

This can be a useful command to quickly execute some radare2 operations
in various positions in mid of a debugging session without the need to
shell out and temporarily transfer process control to radare2.

pwndbg/pwndbg,pwndbg/pwndbg,pwndbg/pwndbg,pwndbg/pwndbg