Added features histogram computation. Some other cosmetic changes.
Added features histogram computation. Some other cosmetic changes.

CVML/vlbenchmarks,andersbll/vlbenchmarks,andersbll/vlbenchmarks,CVML/vlbenchmarks,andersbll/vlbenchmarks,vlfeat/vlbenchmarks,CVML/vlbenchmarks,andersbll/vlbenchmarks,vlfeat/vlbenchmarks,vlfeat/vlbenchmarks