Cleanup all pthread_cleanup_push / pop pairs so that pop is always called after push, or ASSERT(0) is some grave errors

 * Restructuring:
   * libfreeDiameter:
     - renamed folder & binary into libfdproto
     - renamed libfD.h into fdproto-internal.h
     - removed signals management (replaced by triggers in libfdcore)

   * freeDiameter split into:
     - libfdcore (most contents)
        - renamed fD.h into fdcore-internal.h
	- added core.c for framework init/shutdown.
	- new triggers mechanism in events.c.

     - freeDiameterd (main, command line parsing, signals management)

   * tests:
     - now in top-level directory tests.

 * other changes:
   - fd_dict_new now returns 0 on duplicate identical entries.
   - fixes in dict_legacy_xml
   - fixes in some dictionaries
   - moved FD_DEFAULT_CONF_FILENAME definition to freeDiameter-host.h