* Change to new logging format (closes#542)
* Adds a screenshots folder that uses the application startup time
* Creating focus nodes for VRT files if the info files contain location information
* Fix issue with removing virtual properties
* Add a method for returning the cartesian coordinates for a geolocation on a planet
- Change Time class to become a non-singleton
- Move ownership of the current time to TimeManager(instead of singleton access).
- Store the Time as a Syncable in TimeManager instead of representing all member variables of Time as Syncables.
- Pass a Time object around in the update/render methods, so that renderables don't have to query the OpenSpaceEngine to know if time is paused or if it jumped.
- Introduce Timeline and Keyframe classes
- Make use of Timelineand Keyframeclasses in KeyframeInteractionMode and TimeManager
- Added basic unit tests for Timelineand Keyframe
Future work: Add interpolation schemes for keyframes. Possibly use keyframes+interpolation feature to tween/morph properties, or figure out if this should be a separate mechanism.