Switched Time to use a thread local storage model.
Removed shared cast, now calls copy assign op.
Added ability to check if on main thread, check to Time.
Merge branch 'develop' into feature/TLSTime
Switched times to be in seconds.
Fixed build on DMD 2.064.2.
Merge pull request #135 from Circular-Studios/feature/TLSTime

Feature: Thread Local Time