added one-time save and load as a ceci base behaviour for bricks to exploit
added hasData() and minor code clean
Merge pull request #2314 from Pomax/localsaving

added one-time save and load
maze brick and sprite editable
Merge pull request #2318 from ScottDowne/mazeandtile

maze brick and sprite editable
fix issue #2253
Merge remote-tracking branch 'mozilla/develop' into fix-#2253