VocabBuildDB/VocabBuildDB.cpp
* Changed usage text to make it more explanative.

VocabLib/include/VocabTree.h
* Saving and loading attributes holding the number of database images.

VocabMatch/VocabMatch.cpp
* Added to the program arguments the path to the foler where to save the files with the ranked lists of candidates for each query.
* Released some matrices in a try to decrease memory requirements.