New QML animation system backend

Goals:

• Better performance: instantiation and any other overhead found in profiling
• Allow transitions to be used as templates: allow a single transition to control multiple simultaneous "instances" of itself.

This task should support the work being done on view animations, to ensure the resulting API and performance are excellent.

Implementation Backlog

• Investigate/refactor the current Qt Animation Framework
• Add template transitions support to QML animation
  • Remove QObject dependencies from animation classes
  • Remove unnecessary private classes
  • Remove unnecessary variant animation class
  • Make sure all unit tests still pass
  • Benchmark comparison (>=20% improved)
  • Rename Q*Animation2 to better names
• Implement tasks in JIRA which is feasible now with the new animation framewok
  • QTBUG-19969 Need way to drive Animations explicitly, not over set duration only
  • QTBUG-17552 Changes to Animation's 'to' and 'from' properties ignored while animating
  • QTBUG-16969 Need better way to build state machine out of QML states
  • QTBUG-16375 Support grouping of identical Behaviors
  • QTBUG-13927 Animations in transitions do not set running property, transitions do not have running property
  • QTBUG-11098 Improve alwaysRunToEnd support for complex animations
  • QTBUG-13268 Bindings in transitions not evaluated (from property in animation)
  • QTBUG-11001 Warn on (or prevent) simultaneous conflicting animations
• Performance measurement and tunning
  • Make animation timer works well with scene graph's VSync mechanism
  • Rework/cleanup QUnifyTimer2 class
  • Merge duplicated data members between QDeclarativeAnimation classes and QAbstractAnimation2 classes
  • Lazy creating animation instances
  • PathAnimation, SpringAnimation, and SmoothedAnimation all have special cases that need to be implemented to properly support lazy creation and transition templates.
• More benchmarks and tests