Adapted tests for "Obtaining Stored Categories" and "Search" regions
SearchModel builders are made internal to have access from tests
All tests are adapted fro category builders
Builders are made as properties
Introduced CategoryBuilder
Moved more tests to CategoryBuilder
Merge remote-tracking branch 'remotes/ben/Sitrus' into DUI-CategoryBuilderTests
Merge pull request #176 from vmoyseenko/DUI-CategoryBuilderTests

Rewrite unit tests for categories manipulation
Merge branch 'Sitrus' of https://github.com/Benglin/Dynamo into Sitrus2015