Test nesting brick references

fixes #827 

Added bricks sometimes disappeared because they were accessed with an invalid negative index in the brick list. This index was the result of wrong nesting brick references (e.g. with the old version of Tic-Tac-Toe), which are due to our former faulty CopySprite-implementation.

The PR fixes it twice:
1. Correct wrong references directly while projects are loaded (autocorrect mode)
2. Checking index bounds on long click in BrickAdapter (if somehow the index is still wrong) 

Testrun:
https://jenkins.catrob.at/job/Catroid-Multi-Job-Custom-Branch/989/
Only WebviewTest timed out due to some reason --> Internet connection?

Please review with me before merging ;)