Fix spec and enable strict
Put cmd line parsing into own function

- it is called when entering text within the omnibox so the default
  suggestion always reflects the current state
- and it is called on entry of a full command line since that's when
  dispatch is done with the entered command
Fetch documents as strings

- since the extension needs the full string form anyway to build the
  import blob, there's no need to use a document, then turn it back into
  a string
Consistent quoting style
Update TODO
Use an actual Fcommand document string

- update example/load-jquery.html fcommand
- re-discovering that the Fcommand will have to be injected into the page
  if it wants any access to the page's JS.  This will require some
  substantial changes in the content script, since it will no longer be
  evaluating the Fcommand code
- update TODO with thoughts on how to do it
Drop support for documentURL retrieval

- only support documentString
Update TODO

- latest musings on how to reduce security risk and not pass around code
  that gets executed in bg