First commit

Just first commit
Modified gitIgnore

GitIgnore modification
File reference fixes

Removed deleted file references from the project
SLTAsset ported

SLTAsset changed according to AS3 changes.
SLTLevel finalised, SLTBoard, SLTBoardLayer added / ported.
SLTCell_Private commented to remove later.
SLTLevelPack added / ported
Added / Partly implemented SLTCells and SLTCellsIterator.
Need to finalise and fix weak reference.
SLTCells and SLTCellsIterator finished.
as3 changes applied.
Added SLTChunk and SLTMatchingBoardLayer classes, but still to implement and fix them later
ported SLTChunkAssetRule
Ported SLTMatchingBoard.
Partly implemented SLTChunk

Some TODO’s steel needed to implement
Merge branch 'tigr-changes'