Add interface definition for logger module
Add logger/module.c to CMakeLists.txt
Add stubs for logger module
Add implementation for ws_logger_new()
Added singleton cleanup function
Add basic implementation for ws_log()
Fix: Move logger type to source file
Fix: Interface/Impl. of ws_logger_new() to return status instead of logger object
Fix: Use early-return in ws_log()
Allow NULL as etc value
Reimplemented logger for less overhead
Merge pull request #56 from matthiasbeyer/add-logging

[WIP] Add logger module
Add prototypes for (de)initialisation of the compositor
Add initial implementation stubs for interface
Build compositor module
This added the header definitions for monitors
Adding implementation of monitor finding
Do not export the deinitialisation in the interface

Use the cleaner instead.
Moved static functions to end of file