Adding Haar cascade files for nose and mouth
The Haar cascade files for nose and mouth detection were missing
(surprisingly!) from the /data/haarcascades/ directory after the latest
merge. Adding the same because my code uses the 2 cascades for detecting
nose and mouth as facial features.
Revert the previous commit
The mcs cascade files used by facial_features.cpp namely
haarcascade_mcs_nose.xml and haarcascade_mcs_mouth.xml have been moved
to the repo opencv_contrib/modules/face/ due to some licensing issues.
The previous commit placed them back in the opencv/data/haarcascades/
directory which is not a good idea! Any code that used the mcs cascades
will take the link to the XML files as input from the user (until a
work-around is found).
Nose and mouth cascades as commandline arguments
The mcs haarcascades for nose and mouth have been removed from the
data/haarcascades directory due to some licensing issues. So, the code
has been appropriately modified to include them as command-line
arguments. Also, some variables have been declared global (some minor
refactoring) which would help in modularizing the code at a later stage.
Modularizing facial_features.cpp
Split the code for facial_features.cpp into separate functions that
detect the face, eyes, nose and mouth.
Remove false positives from mouth detection
A simple condition was added to remove false positives in the case of
mouth detection which says that the centre of the bounding box denoting
the mouth must be lower than the centre of the box for the nose.
Documentation added
Some documentation was added along with minor changes to the code to
make it adhere to the OpenCV coding style guide.
Merge branch 'test'
Resolved a modify/delete merge conflict

Conflicts:
	samples/cpp/facial_features.cpp