v0.3.0: Added 2D Gabor filter (#57)

* Added function to construct 2D Gabor kernel.

* Modified gabor function to include imaginary part of the filter.

* Added tests for gabor filter function.

* Modified gabor function and placed validate_gabor outside of gabor.

* Added warnings for cases when size_x or size_y is not positive.

* Added test cases for errors/exceptions.

Fix gaussian for width 0

Merge pull request #43 from JuliaImages/teh/gaussian_width0

Fix KernelFactors.gaussian for sigma = 0

mapwindow docs and parser depwarn

Merge pull request #40 from JuliaImages/teh/nodepwarn

Circumvent a deprecation warning

Fix errors on 32bit

Merge pull request #38 from JuliaImages/teh/fix32bit

Fix errors on 32bit platforms

Julia version bump and syntax updates

Merge pull request #37 from JuliaImages/fbot/deps

Fix deprecations

v0.1.4: Merge pull request #30 from JuliaImages/teh/non1_inputs

Fix padding for inputs with non-1 indices

Works on 0.6

Merge pull request #29 from tkelman/patch-1

more specific version cutoff for type system rewrite

Usability and functional improvements in detecting/fixing overflow

Merge pull request #23 from JuliaImages/teh/tempfiles

Clean up temporary files in tests. Fixes #8.