A lot of things including new save/load. Please test.
 Changes to be committed:

	modified:   WPScore/WPLib.cpp
	modified:   WPScore/WPLib.h
	modified:   WPScore/WPScore.cpp
	modified:   WPScore/WPScore.h

WPScore::save/load with compression, namely SFF 0b. Please test!
 Changes to be committed:

	modified:   WPScore/WPPart.cpp
	modified:   WPScore/WPPart.h
	modified:   WPScore/WPPersistentTree.cpp
	modified:   WPScore/WPPersistentTree.h

Accoring to Pt-Cr's requirement, WPPart::getNotesByInterval(.) is added.
Merge branch 'master' of https://github.com/bg95/WhitePigeon into Pt-Cr