Property setters can now return value

Allow model property setters to return a value after processing so
custom handling is not necessary.
Fix bad indentation :(
Allow non truthy values to be returned by setter
Property setters can now return value

Rollback- recommit to bundle changes...

Allow model property setters to return a value after processing so
custom handling is not necessary.
Merge branch 'property-setters' of https://github.com/megawac/Epitome into property-setters
reindentation...
Merge pull request #14 from megawac/property-setters

Property setters can now return value