* Improved stroke curvature
* Added drawables: rectangle, ellipse, line, triangle
* Added stroke erase (buggy)
Merge remote-tracking branch 'origin/master'

Conflicts:
	app/src/main/res/layout/activity_my_activity_drawer.xml
* Improved stroke curvature
* Added drawables: rectangle, ellipse, line, triangle
* Added stroke erase (buggy)