Merge pull request #8 from morevnaproject/master

Update build script for Cairo and Boost dependencies.
Core implementation of disabled keyframes.
Keyframe activate/deactivate button
Add keyframe toggl checkbox
Make sure to initialize keyframe state.
Fix loading of keyframe state
Fix bug: Keyframes widget not updated when keyframe is added.
Fix bug: Keyframes widget now redraws on keyframe change or remove events.
typo
Ignore deactivated keyframes. Selection on keyframes widget is broken.
Fix keyframe selection in keyframe widget
Don't affect waypoints when inactive keyframe is moved.
Fix bug: Timetrack panel is not updated when empty keyframe is moved
Fix bug: On keyframe move previous item in keyframes list dock should update its length value.
Don't forget to initialize old_keyframe_list
Remove keyframe toggle button.
Ignore waypoints when deleting disabled keyframe
Force update timetrack if empty/disabled keyframe removed.
For some reason the state of the keyframe is not always passed correctly. Make sure to get it right.
Use queue_refresh for Widget_Keyframe_List