Add module for finding libev
Add libev as a dependency to CMakeLists.txt
Merge pull request #36 from neithernut/add-build_env_libev

Add build env libev
Change C standard to GNU99
Re-Add threading functionality
Re-added ref counting members in ws_object type
Add helper functions for shorter lock/unlock calls
Add implementation for ws_object_getref()
Fix: const keyword location in object callback typedefs
Add free callback type for object type
Add implementation for ws_object_unref()
Remove lock checker functions
Add lock initialisation
Make ws_object_get_id() threadsafe
Make ws_object_get_settings() thread-safe
Make ws_object_set_settings() thread-safe
Simplified ws_object_run()
Add missing rw lock init calls in _new() and _init()
Remove: unref callback. It is useless
Rename "free" callback to "deinit" callback