Copy report images and assets so that it can be archived
Remove the HTML reporter view class, use a single one
Use `FileUtils.mv` instead of `File.rename` in compiler
`mv` works across different partitions, `rename` doesn't (hard link)
Only attempt to copy files that exist
Add a `--reports-dir` option
Write relative assets and images paths to the HTML report
Ensure screenshots sorting by name
Didn't always sort them correctly for me
Actually create subdirectories for different features
OMG, this was really confusing
Merge pull request #33 from zucchini-src/archive_report

Archivable HTML Report, closes #7