Documentation, fixes, improvements

+Documentation update
+Fixed edge case when rewinding oldest value
+Properly supporting change of Time.timeScale at any point
+Cleaned CircularBuffer class
+Fixed unecessary memory usage even when user didnt opt to track certain attributes

Documentation update

Update README.md

Rigidbody 2D

+System now correctly tracks velocities of both Rigidbody and Rigidbody 2D

Fixed execution order issue

+Fixed issue with execution order when placing new element to track, that required Unity to be restarted
Interesting note: OnEnable() of RewindAbstract.cs was actually called before Awake() of RewindManager.cs which is apparently not a bug: https://issuetracker.unity3d.com/issues/awake-function-called-after-onenable

Workflow simplification, documentation update, code cleaning

+Added more summaries in code
+Improved Animator rewind method
+Changed and simplified custom variable tracker implementation (AdditionalRestore() and AdditionalReset() not required anymore)
+Timescale is now changeable (although not in runtime)
+Cleared scripts from unnecessary references
+Changed the method name from GetSnapshotFromSavedValues() to Rewind()
+Circular buffer have exposed methods working directly in seconds so the position doesnt need to be calculated anymore
+Simplified RewindAbstract class
+Now also tracking the active state of audiosource
+Updated documentation (More important sections added)

Fixed dinosaur animator transition in demoscene