MUS-93 First sound implementation

Added midi player to play notes from an instrument
MUS-93 Play Sound Test Cases

added test cases for the MidiPlayer class
MUS-93 Added play button and tests

Added play button in the main menu and added new Midi tests
MUS-93 Added play all test

Added play all test
Did some minor refactoring
MUS-93: Added rotation support for MidiPlayer
MUS-93 MidiPlayerMock change

Changed MidiPlayer constructor to support its mock class after the
singleton change
MUS-93 MidiPlayer Bug Fixes

fixed several issues:
- player did not play anything under certain conditions
- player was playing too fast or too slow

added a dialog after clicking PlayAll to stop the music playing
MUS-93 Syntax Fix

fixed a syntax error in the test package
MUS-93 Orientation blocked while PlayAll

Added a feature which blocks the rotation function of the phone while
play all is active. The blocking behavior ends after play all.
MUS-93 Refactoring, Bug fixes

Fixed undo bug after clear and open operation
MUS-93 MidiPlayer tests

Added MidiPlayer test suit
MUS-93 added TODO
MUS-93 added TODO #2
MUS-93 moved file mock

move file mock to an inner class
MUS-93 Added GUI Tests

added GUI tests for the play all feature
MUS-93 Renaming

Renamed some midi player parameters
Merge pull request #7 from Catrobat/MUS-93_Piano

Mus 93 piano