Merge pull request #3 from ahojnnes/censure

Fix bugs in censure keypoint detector and improve code
Changing the variable names of constant objects
Correcting a bug in Line Suppression
Putting constant variables outside the definition
Making the docs more explicit
Correcting the imports
Assigning boolean to the feature mask in line suppression
Actively filtering border keypoints on all scales
Adding tests for all the modes in censure
Debugging Travis error
Reverting back to last but one commit
Making the code compatible with Python 3
Actively filtering border keypoints for all the scales part 2
Removing print statements
Returning mask in _remove_border_keypoints
Filtering out border keypoints using masking
Replacing int32 by intp
Fix several bugs in DoB method and improve overall code quality