Enable minimist options parser

- doesn't do anything useful yet, but it works
Clean up comments
Add tests for content script

- not sure I'm happy with how it's divided up.  Maybe the guts should go
  into a namespace/class.
- test that basic assumptions of the main functionality of the content script
  are true
Remove obsolete comments

- the listener needed to return true because the response func may be
  called asynchronously
Move blob cache allocation where it's needed

- it's only used by the Util object, so keep it in there
Get js module ordering correct
Create link element after validation
Add test for createImportLink

- actually caught a bug, too
Assign properties all at once
Update TODO

- by using document imports, there is no multiple-inclusion guard needed
- executeScript won't work because the injected code has no access to the
  page's own JS.  Using an import doc allows this.
Correct bg module ordering
Don't use deprecated getSelected API