replaced FastReflection with Fasterflect since FastReflection had a concureny bug

in it's cache dictionary and Fasterflect has a more active development
replaced object reference exception with a more meaningful exception when a column is

missing mapping information
minor cleanup in MapRepository,
oops. merge issues.
Merge branch 'master' of https://github.com/kayone/Marr.DataMapper
Fixed a problem that caused two unit tests to sometimes fail due to MapRepository singleton state not being reset during unit test setup.
Removed references in comments and readme to old FastReflection library