Add option to ignore whitespace

[shortstuffsushi]

Hi there,

I've been enjoying your package in sublime so far, but ran into an issue today where I have a file comparison where indentation was added across the whole file, making the diff effectively useless. I was hoping to find an "Ignore Whitespace" option, but it doesn't seem to exist yet. Would you consider adding this as a config or something along those lines? I looked briefly at doing so myself, but I don't really know Python, and it looks like you're using an external lib to do the diffing anyway? Does that lib accept any sort of configs like that?