Performance, ArrayEntryFilter and bugfixes

Performance

Implemented few ways to reduce allocations and improve performance:

• Replaced LINQ with 'For' loops
• Replace Ditionary<Type, Collection> with static generic class

ArrayEntryFilter

This filter allows checking whether the property value is contained inside an array.
Usage:
filter.Property.In=value1|value2|value3

Bugfixes

• ExpressionExtensions.Constant now always use the target property to convert constants to a nullable type.