Updated version number
Include `block` value in Explicit
Renamed ExceptionHandler to Rts, and ! to Wrap
Noted change to ExceptionHandler in CHANGES
Added phantom types to return-type strategies
Made return-type strategy method groups subclasses of RtsGroup
Added a default Rts
Merge branch 'rts-typing'

Conflicts:
	src/strategy.scala
Fixed merge
Tweaked documentation
Added exponential backoff return-type strategy
Decided to use `Mode` instead of Rts.
Introduced new repl object for convenience methods in the REPL
Small update to documentation
Changed source header version number
Renamed returnFutures to returnFuture
Corrected documentation
Added text on REPL mode
Added `modal` method to package object
Removed defaulting mode