refactored the datamappers setup arguments
changed AbstractSitecoreFieldMapper to have GetField and GetFieldValue
changes AbstractSitecoreFieldMapper to have SetField method
SetField changes
SitecoreFieldIEnumerableHandler
SitecoreFieldImageMapper
SitecoreFieldIntegerMapper
SitecoreFieldLinkMapper GetField
more unit tests for SitecoreFieldLinkMapper GetField
SitecoreFieldLinkMapper SetField
fixed missing type specification on some mappers
SitecoreFieldLongMapper
start of SitecoreFieldNameValueCollectionMapper
SitecoreFieldNameValueCollectionMapper tests
SitecoreFieldNullableMapper and additonal TDS items
SitecoreFieldRulesMapper
SitecoreFieldStreamMapper
SitecoreFieldStringMapper
fixing broken unit tests
glass performance tests and small fixes