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
vectorized transform.integral.integrate
Merge pull request #493 from ChrisBeaumont/vector_integral

vectorized transform.integral.integrate
Inline helper functions of label
Add option to return number of labels
Add test case for number of labels
Rename development guidelines, so they are shown when opening a new PR
FIX use specific structuring element in Canny
Merge pull request #498 from JDWarner/fix_canny_strel

Use specific structuring element in Canny function
Merge pull request #497 from ahojnnes/guidelines

Rename development guidelines, so they are shown when opening a new PR
Merge pull request #484 from almarklein/3d-selem

Adding predefined structuring elements for 3D morphology.
fix to preserve input image shape upon executing `random_walker`