* Modification time is now updated when writing a file
* Refactored constants into a separate file
* Added a software metadata to help identify schematics created with litemapy and the version used
* Added a DiscriminatoryDictionnary class to store regions in schematics while making sure they fit in
* Regions are now stored in a read only discriminatory dictionnary of the schematic, using their names as key
* Trying to add a region that does not fit into a schematic raises an error
* Region's names are not stored in region anymore
* Region's positions and sizes are now read only
* Region's palettes are now private
* Schematic's size is now read only