if a read from the remote tracer's socket fails, let's smash
the socket and wait for another remote tracer

it's buggy. Next commit to fix it.

The problem is if the tracer exits while sending a message.
The local tracer will not get it full and will throw garbage
to the T in the tracee, leading to some bad things...

plus some cleanup here and there

get rid of forward.c, make everything static inside local.c

remove forward stuff from defs.h
remove defs.h from local.c and forward.c

The local tracer now waits for the remote tracer to connect,
that's no more the other way around.

All the remote tracers (textlog, enb, vcd) have also been converted.

first step: let the tracee connect before the remote tracer
and let's have a "no wait" mode where the local tracer starts
the tracee before the remote tracer is connected

plus there is a default now