Add filter support to queries
Merge branch 'filters-sp' of https://github.com/cardinal252/Lucinq into filters-sp

Conflicts:
	Lucinq/Interfaces/ILuceneExecutor.cs
	Lucinq/Querying/LuceneSearch.cs
	Unit Tests/Lucinq.UnitTests/IntegrationTests/DateFieldTests.cs
Add helper for date range filtering and update code
Update date collector to use longs instead of strings
Merge branch 'filters-sp' of https://github.com/cardinal252/Lucinq into develop-30
filters brought in & bug fixes