Contrasharpen updates

[ghost]

Ideally all forms of contrasharpen should be merged into a single function with the following features:

• Allow the user to specify a custom blur function/clip
• Allow the user to specify a custom sharp function/clip
• Allow the switching between Median and absolute difference limiting

With these we can keep the functionality of all the existing contrasharpen functions, but into one universal script instead.
To easily replicate behavior of the old scripts we can make presets for their different approaches to blurring, sharpening, etc.