1. SGenerator : Resource Parser
2. Some minor changes
Establish a basis of Keyboard
Merge remote-tracking branch 'origin/Toi'

Conflicts:
	res/layout/activity_main.xml

For rehearsal.
Some arrangements and optimizations.
Keyboard : Multi-touch.
Additional piano resource. (C4 ~ B6)
Improve functionality of Keyboard:
	1. can distinguish invalid key set.
	2. uses density independent pixel unit.
	3. indicates every C by text.
Improve functionality of SGenerator:
 - Sustain stream when key is pressed
 - Fade out stream when key is released.
우측 스크롤