MUS-99 Added max track size

Added a feature so that the user can only have a maximal amount of X
elements in a single track
MUS-99 Refactoring

Changed the name of the max track size so that we represent both:
symbols count and note event count (1 Symbol = 2 Note Events)
MUS-99: Text View for track size
MUS-99: Refactoring
MUS-99: try to fix jenkins issues#1
MUS-99: try to fix jenkins issues#2
Update build.gradle
Restore build.gradle
Merge develop
Merge pull request #14 from Catrobat/MUS-99_DrawPerformance

Mus 99 draw performance