[cmyth] Cosmetics in event.c
[cmyth] Cosmetics in socket.c
[cmyth] Refactor cmyth_rcv_data

This function receives raw data from the socket and thus can be used to
get all data being leftover in the socket.

Note that this private function was not used anymore, but will be used
later for the above purpose.
[cmyth] Use cmyth_rcv_data in cmyth_rcv_okay

Improve receiving leftover data in cmyth_rcv_okay by using
cmyth_rcv_data instead of cmyth_rcv_string.
[cmyth] Clean leftover data in cmyth_event_get_message

Some events received in cmyth_event_get_message were able to break the
event connection completely by leaving back leftover data on the socket.
(Example: GENERATED_PIXMAP)

This is fixed by using cmyth_rcv_data at the function end.
In addition, events that are not interested in further data, can now
simply ignore it and don't have to read everything.