Added support for conditinal lazyloading

replaced reflection for setting/getting properties with compiled expressions.
revered SortBuilder to use '_useAltName'
Merge branch 'master' of https://github.com/kayone/Marr.DataMapper into kayone-master
- Added ResetMapRepository method to TestBase classes for UnitTests and IntegrationTests
- IntegrationTests project can see internals of Marr.Data for test purposes (to reset MapRepository before each test)
- Renamed a few test namespaces