Add info about using dsf as a "normal" diff tool
Add info about using dsf as a "normal" diff tool

diff-so-fancy is great for git of course, but it's also very nice to use
for just normal diffs between two files

Fixes #328

scottchiefbaker/diff-so-fancy,so-fancy/diff-so-fancy,scottchiefbaker/diff-so-fancy,so-fancy/diff-so-fancy