move sccp_main.c content in sccp.c
move protocol / message related enum to sccp_message.h
use enum values instead of literal values
move softkey and softkey set definition to sccp_message.c
remove checks for null in handle_message

* the thread session is always working on a valid session and message
* handle_message is only called from thread_session
* handle_message delegates calls to handle_message_*
* this was getting a bit noisy for not much
Merge branch 'master' into move

Conflicts:
	xivo-libsccp/src/sccp_device.h
add sccp_utils.h to Makefile.am
add sccp_device prefix to functions working on sccp_device
remove check for device null on sccp_device_* functions
move device_type_str in sccp_message.c
move line_state_str in sccp_message.c
rename *_str functions
more sccp_ prefix
don't use default case when using all cases of an enum
rename sccp_new_line to sccp_line_create
remove check for line null on sccp_line_* functions
update unit tests
update name of sccp_config functions
update null checks on sccp_config functions
Merge branch 'move'