Add gabor filter function
Fix meshgrid bug in gabor kernel and argument passing
Add test cases for gabor filter
Add example script for gabor filter
Remove unnecessary kernel description for filtering
Rename sigma parameters by adding an underscore as separator
Fix kernel-size calculation for non-zero theta.
Add `bandwidth` parameter to `gabor_kernel`

Note that this changes the API of `gabor_kernel` and `gabor_filter`: The input parameters are rearranged and positional arguments are changed to keyword args.
DOC: Tweak docstrings for Gabor filter
Update gabor example.

The parameter order to `gabor_filter` changed so this example was broken. Also, add plots of the Gabor responses to the demo.
Merge pull request #2 from tonysyu/gabor

Change API for Gabor filter
Add better test of gabor filter
Merge pull request #3 from tonysyu/gabor

Add better test of gabor filter
Merge pull request #371 from ahojnnes/gabor

Gabor filter