improved import of color BMP (fix by Florian Sella)
fixed RandomForest documentation
fixed typo in comment
fixed rounding error in createResamplingKernels() (resolves #137)
small random forest documentation fixes
Improved libpython search. Now works inside a virtualenv, too.

1. Use HINTS instead of PATHS (other than PATHS, HINTS are searched
   before the system defaults)
2. Searching the default paths, too. Required inside a virtualenv.
added RandomForest constructor argument 'label_count'
vigranumpy RandomForest constructor: provide the list of labels rather than their number