Simplified activation routines using closures rather than expressions where
possible. Small perf impact, much more readable code. Eliminated possible
deadlock by forcing 'parent scope' composition to happen under its own
CompositionOperation, ensuring locks are released before the composition
process moves back down to child scopes. (Acquisition order is always
strictly child-then-parent.)

Parameter renames to improve readability.

Better implementation of ReflectionContext property projection without redundant
hierarchy search.

Fixed bug preventing use of RegistrationBuider with types that carry
multiple properties with the same name.

Fixed possible deadlock under failure conditions in shared instance management
code by pulling monitor enter/exit calls out into a disposable object enclosed
within a using block.

Minor tidy up to remove redundant code.

Added s.r.context to composition provider nuspec.

Significant perf improvement replacing dictionary with sparse array class in
LifetimeContext.

Fixed race condition whereby shared instances could be seen by other threads
before property injection or OnImportsSatisfied() completed.
In the process introduced an additional dictionary lookup for initialization
of shared parts, and had to remove the shortcut singleton lookup trick. Perf
degraded a fair bit as a result of this, could be improved significantly by
switching the _instancesUndergoingInitialization dictionary in LifetimeContext
to another more suitable data structure;

Fixed typo in package Id.

Reorganized repository to include updated MVC composition provider and lightweight composition packages.

Updates for Preview 5.

Updated trunk to MEF 2 Preview 4.