gmrender source files import.

UPlayMusic is first based on GMRenderer-resurrect.
https://github.com/hzeller/gmrender-resurrect
the last commit of this import is 61f5a8fe72
install the build scripts

scripts.mk contains makefile rules to build libraries, and binaries
build scripts need to make the build directory for each package
output is a external module loader.

to implement the external loader the search of modules is not more static but request an entry from output_module.c
decrease the glib dependancies

some functions used gint64 and gboolean from glib.h .
This dependancies are useless.
functions upnp_start and upnp_stop

some code lines from main.c is allowed to create a library
allows to clean shutdown renderer

renderer structure contains a shutdown function called by the device
the shutdown function of the renderer must be declared first
device description changeable

friendly_name, udn and serial number may be changed at the startup
wait 1s to send information instead 500ms

thread_update_track_time waited 500ms with usleep.
usleep is not allowed in some cases with signals handler. To be complient as library nanosleep is saver.
pilot libraries

pilot_atk and pilot_mods are two small libraries from the github of mchalain

pilot_atk is a Application Toolkit written in C with signal/slot feature
pilot_mods is a module's toolkit written in C. It loads modules from a directory and check the type of the library
modules gstreamer, debug, system, mpg123, tinyalsa

gstreamer is the module developped for gmrenderer
debug is a module to print the action from the UPnP controller
system is a module which executes commands on each UPnP controller action
mpg123 is a mpg123 decoder
tinyalsa is another type of module to play sound on the sound card with tinyalsa
missing include for ithread declaration
build the gmrenderer webserver

the gmrenderer webserver uses data in memory. This option allows to response quickly to the UPnP controller but that use a lot of memory.
Other parts could be optimized to. But to optimize part by part, we split the code in several library.
application source code

this application uses pilot libraries but it should be easely to generate another application without this libraries
logging.c a wrapper for gmrenderer logging
upme.conf a configuration file mandatory to run