Change from rmagick -> mini_magick

Change from rmagick -> mini_magick - contributed by @boris-petrov

Ensure to write .new images on image dimension mismatch

Changelog

Version: 3.0.1

Fixes a minor issue that when the image dimensions are not the same it now generates the .new images as before (previously the image dimension mismatch was handled by compare, but now it appears that its possible that it will return the diff pixel count. So now we've implemented a check, which didn't correctly follow the same workflow as before. It does now.

Several updates and new percentage pixel_threshold support

Changelog

Version: 3.0.0

• Updates the gemspec to allow newer version of rmagick and rmagick4j
• Simplifies the command wrapper class to only execute the command nothing else
• Introduces a new comparible module for page and element to do the comparing simplifying the Comparer class considerably, and making unit testing these much more easily
• Supports percentage pixel threshold, with the support of a new threshold calculator
• Adds deprecation warning for pixel_threshold configs that don't pass a Hash config, but continues to support current users for backward compatibility
• Adds a new image container to validate the base and new images are of the same dimensions. Previously compare would have complained - however it appears that newer versions of compare don't error when the base and new image are of differing dimensions meaning that for percentage config, it would incorrectly pass, so this is an additional guard to prevent that.

Development improvements

• Adds rubocop and linted all code to make consistent for new contributors to use
• Fixes some random flakey specs due to modifying config state leaking into other specs

Support JRuby

This release supports JRuby as contributed by @boris-petrov #16

1.2.0

Update the gem version to 1.2.0

1.1.1

Fix error with non-existent method calls to the rmagick library.

1.1.0

This release removes the chunky_png and replaces it with rmagick due to performance issues for our use case.

1.0.0

Update to first major version and update README

0.3.1

Increase minor version for new release

 - allow find to find hidden elements as well

0.2.0

Ensure to not execute js when the element is undefined