refs #6447 Existing test fixed and enabled
refs #6447 most tests and some controversial changes

to the MDBoxFlatTree methors (boxID !=boxNum?
refs #6447 fixing Unix warning
refs #6447 fixed erroneous test suite name
refs #6447 Thorough test for all suspicious places.

Tested the pieces of code where changes can be expected
refs #6447 Doxygen error
refs #6447 Added pDoc->release()

Hate to use features I do not understand to the code I have not written but it seems does not do any harm
refs #6447 removed unnecessary memory release operators from BC
refs #6447 Changed the order of operations in the test suite suggested

by tester. Though I believe the previous order was more suitable highlighting the internal variables used by the suite right from the beginning.
refs #6447 Made better comments around (from) commented piece of code

in BoxController.cpp == operator. Comments are necessary to highlight the assumptions, made when defining the operator.
refs #6447 Syntax improvement.
Merge remote-tracking branch 'origin/feature/6447_UnitTest4MDBoxTree'