Sort dependencies in package.json
annotator: Fix installation of wicked-good-xpath

This was testing the type of the wrong object, and thus
wicked-good-xpath wasn't being correctly installed.
Install wgxpath shim for IE9+ in the test runner

This commit adapts the work done in opengovfoundation/annotator-ie-shims
to make our tests pass in IE9+.

Left as an exercise for the future:

- including the shim in a built package
- IE8