Adding the new TreeBehavior file
Initial implementation for find('path')
Testing the implementation of find('path')
Adding another test and reverting teporal change
Agging another test for a tree with another root
add childCount method
fix typo, and childCount()
update test's docblock
allow callable scope
added fixture and test case
revert
update test cases
update childCount()

remove unnecessary scoping when couting by ID
correct version in docblock
added children method

also,first attempt of moveUp()
children() & moveUp completed

test cases updated
fix `Use classes must be in alphabetical order`
more PHPCS=1 fixes...
update, code adjustments

- getMaxOrMin visibility
- strict comparison.
update refactoring of children() method

- is now find('children')
- test cases updated