new BubbleGraph added
Bubble size caculation method improved.
Overwrapped area deletion added ( one-way )
Feature about delete overwrapped lines added.
Merge branch 'master' into BubbleGraph

Conflicts:
	sample/AndroidManifest.xml
	sample/res/values/strings.xml
	sample/src/com/handstudio/android/hzgrapher/MainActivity.java
Merge branch 'master' into BubbleGraph

Conflicts:
	sample/AndroidManifest.xml
	sample/res/layout/activity_main.xml
	sample/res/values/strings.xml
	sample/src/com/handstudio/android/hzgrapher/MainActivity.java