Remove these because I'm too lazy to convert them to proper
STREAM_CTRLs. Considering that probably nobody uses radio://, caring
about this is a complete waste of time. I will add these commands back
if someone asks for them, but I don't expect this to happen.
Since m_option.h and options.h are extremely often included, a lot of
files have to be changed.
Moving path.c/h to options/ is a bit questionable, but since this is
mainly about access to config files (which are also handled in
options/), it's probably ok.
