Common/FunctionUtils.hpp
* Declared DynamicMat class for holding a matrix not held in memory but
in files.

Common/FunctionUtils.cpp
* Defined DynamicMat methods.

VocabLib/include/VocabTree.h
KMajorityLib/include/CentersChooser.h
* Moved from cv::Mat to DynamicMat.

VocabLearn/VocabLearn.cpp
* Loading files and computing the merged matrix statistics while saving
in an index the row id and file id association.