Fix primary test, rearrange fixtures, add results files

Writing output with string concatenation in test.js is messy and doesn't scale.
Puts source fixtures in "source: and adds a "results" dir with expected compiled
CSS files.

Because the erroring file will have different stack traces per environment, we
need to test that it exists in a roundabout way. Could be cleaner.
Re-implement and improve error logging
Remove OS Temp dir on every run

Temporarily adding this for easier work with logs and errors. This is the
keystone of the caching issue that has to be resolved.
Add file and inline sourcemaps with gulp-sourcemaps

This makes sourcemaps option a bool in order to provide consistent integration
with gulp- sourcemaps. If people complain we can allow sass option strings to
pass through and do gulp style when the option is passed a bool.
Add index.html and gulpfile.js for testing sourcemaps

I've been using these, probably good to make available to everyone else.
Directions on use in the html file.
Allow single file source values, move cleanup to after task completion
Update readme, reduce length and emphasize our options

- Update for new sourcemaps
- Update for sourcemap adapter
- Add recipe for running two sass tasks at the same time

	I explored adding smart container switching to the plugin but I think it will
	interfere with any type of incremental build / caching that we add. Specifying
	an option isn't a hard request to make to our users either.