Add missing newlines at EOF in sources

(missing newlines break build due to -Werror)
Fix "comparison is always true due to limited range of data type" warning
Update Messenger.c

Offer more meaningful returns so appropriate actions can be taken by the GUI.
Merge pull request #183 from Proplex/master

Update readme with tutorial videos
Merge branch 'patch-3' of https://github.com/Astonex/ProjectTox-Core into Astonex-patch-3
Small fixes.
Update CMakeLists.txt

This thing requires libconfig but doesn't test for it...
Create FindLibConfig.cmake

Warning, this is a google snippet, but works fine, shouldn't be an issue
Merge branch 'patch-1' of https://github.com/Teknocrat/ProjectTox-Core into patch-1
Merge pull request #187 from Teknocrat/master

libconfig dependency
Update readme.md

Basically, a few words tweaked here and there, to make the file more gramatically correct.
Update nTox.c

Made the help message a string type.
Add detection of required libraries
Fixed cpu usage
Clean up/format code
Adding homebrew commands to INSTALL
stat file before attempting to open
Create start_guide.de.md

Translated the original small documentation to german.
Create start_guide.md

Written by charmlesscoin.
Fix space/tab indentation