Add ImageComparison.compare which indicates the result via a return value instead of throwing exceptions.
Move detection of missing reference images into ImageComparison.compare.
Move ImageComparison.write to ImageMismatchException (it's only caller)
Move throwing of UnrenderableException from ImageComparison to ImageRenderer.
Merge branch 'master' of github.com:avh4/imagecomparison
Optimize imports.