Update VLFeat to 0.9.17
Removed namespace alias from header file
Added verbosity to kdtree
Added vocabulary serialization
Added serialization of kd-tree depth
Removed unused attribute from Vocabulary
Using ENABLE_TESTING definition
Minor cleanup
Added reference matlab code for test_vocabulary
Removed dependencies tarballs

It actually makes no sense to store dependencies, which can be
downloaded and compiled into this directory.