* add a pid file option on command line + implement it
* make the relative path in conf param relative to the configuration
file directory and not the running directory
as many configuration paths can be relative to the execution working
directory, this directory is recorded at launch time, and the set_params
function does a chdir(<start work dir>); <load conf>; chdir("/") when
it's called.
* split the rfc3161 and the http part
* add a logger function
* add a debugging logger function for the requests
* add a specific handler for rfc3161 request
