KMajorityLib/include/Clustering.h
* Refactor due to changes in KMajority class.
* Comments cleaning.

KMajorityLib/include/KMajorityIndex.h
* Declared method for creating an index to address descriptor mathching.
* Using an index for descriptor matching, declared a method to create a
desired type and an enum holding the possible types.
* Re-named class to a more consistent one with its job.
* Re-ordered class attributes and changed accesibility of some methods
and attributes.
* Changed pointers for STL vectors.
* Updated some methods doc.

KMajorityLib/src/BOWKmajorityTrainer.cpp
* Refactor due to changes in KMajority class.

KMajorityLib/src/KMajorityIndex.cpp
* Changed pointers for STL vectors, hence variables holding pointers
length disappeared.
* In method cluster, handling empty clusters correctly.
* In quantize method, using an index to address descriptors matching.
* Defined method for creating an index of desired type.

KMajorityLib/tests/.gitignore
* Ignoring tests executables.

KMajorityLib/tests/KMajority_test.cpp
* Implemented some tests for KMajority class.

KMajorityLib/tests/Makefile
* Copied makefile from that of VocabTree tests.

VocabLib/include/InvertedIndex.hpp
* Minor changes, using equality operator without explicit calling it.

VocabLib/include/VocabTree.h
* Factored out the inverted index to another class.
* Removed computeNodeStatistics method since it was a vestige.
* Included number of tree nodes in the save/load methods.
* Deleted code for handling empty clusters, it was doing nothing useful.
* Using number of tree node as tree size instead of only the number of
leaf nodes.

VocabLib/tests/VocabTree_test.cpp
* Refactor due to changes in VocabTree.
* Re-ordered tests.