Place repo details in the url.
Set the branch to '', that makes it use the default.

It also means the repo in the url does not by default contain /branch/master.
Merge branch 'master' into repo-in-url
Improvements suggested by @philschatz and @tmsp1
Remove the onchange handler when the view closes.

Without this, there is an accumulation of content change handlers on
jquery, n-1 which does nothing good.
Merge pull request #41 from oerpub/performance-enhancements

Avoid piling up of content-change handlers
Merge branch 'master' into repo-in-url
URLEncode the id as a whole, not as a component.

This simple change means that a slash (/) is no longer encoded as %2F. This
makes the url much easier to read.
Remove accidental addition of underscore dependency
Merge branch 'repo-in-url' into testing