Added missing IntRange definition.
Tp.Allocation: added comments.
Tp.Test.Core: added comments
Tp.Position: Renamed to RowPosition (as position means various things.)
Tp.Allocation: added function convert_from_index, convert_from_finger_position
changed terms used in Allocation: Position into index: as position is used to point the fingers also.
Tp.Test.Core: added test case allocation_convert
Tp.Allocation: corrected convert_from_... functions to fullfil test case.
Separated Enums and Constants in tp_enums.vala