removing unnecessary function pointer _isset variables
fixing minor memory leak of friendlist
rewrite of get_id function
Update prompt.c

Make id uppercase.
prefer param over static

Conflicts:
	testing/toxic/main.c
Merge branch 'master' of https://github.com/naxuroqa/ProjectTox-Core into pr
add header guard and includes to windows.h
remove externs in favor of includes
move windows functions to its own file
remove temporary callbacks from refactoring
Merge branch 'master' of https://github.com/mkfifo/ProjectTox-Core into pr
Merge branch 'remove_externs' of https://github.com/krisl/ProjectTox-Core into pr
Fixed small compile error on my end.
Merge branch 'patch-6' of https://github.com/Astonex/ProjectTox-Core into pr
Messenger fix from pr #461.