[Tree]: some code enhancements
[Tree]: add new `nodecreate` event

now we can build nodes from outside!
[Tree]: add `expander` property to node instances
[Tree]: extract Tree's API
[Tree]: remove obsolete nodeById property
[Tree]: add getNode() method
[Tree]: remove obsolete getText() method
[Tree]: improve setCaption() method
[Tree]: split collapse() from expand() method
[Tree]: improve select mechanism
[Tree]: remove old obsolete methods
head update
head update
Merge branch 'master' of https://github.com/mkhahani/protopack

Conflicts:
	source/tree/tree.js