as TS_RESP_CTX is not thread safe, this commit implement a pool of
TS_RESP_CTX in which a thread can pick one in a thread safe maner.
* implement a ts_resp_ctx_wrapper containing a TS_RESP_CTX and a
lock and bool to mark the availability of the TS_RESP_CTX
* implement the get_ctxw to recover a given TS_RESP_CTX in a thread safe
maner
* adapt the rest of the code to accomodate the new way of doing things
* set the default number of threads to 10 as it's now safe to do so
* 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
* the chdir was done after the loading of the conf file, reversing it
* in case log_level is not set, the application would segfault, now
handled properly (default is info)
* remove logging to the daemon facility
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
