Updated build tool to git.
ComputedFrom - more flexible version of Persisted

New concept ComputedFrom is more flexible version of Persisted it may be
added to any entity or propety. It allows propery-level computation
persistance.
Refactored KeepSynchronized to simplify design.
An IMacroConcept may create an IAlternativeInitializationConcept without setting non-parsable properties.
KeepSynchronized and ComputeForNewBaseItems modified to work with ComputedFrom instead of Persisted. Persisted is now simply a macro concept that generates ComputedFrom.
Merge (ComputedFrom).