More work on time points (more general now). Basic parser for temporal constraints. SOme additions to for temporal databases' support
Small fix: StateModifier goes from Iterable to Seq
Changed references to action/variables from strings to Ref. This enforces correctness of references though static types.
Some clean up on abstract/concrete temporal annotations and timepoints.
Add instance declaration to state modifier
Some more java friendly functions.
Comments on Action.scala
Typos, fixes in doc/problem definition
Change references to have default constructor and use integer as internal id