Replace Array.reduce with simpler loop.

For https://github.com/openannotation/annotator/issues/411
Rewrite tests to not use plugin.configure
Relates to issues from https://github.com/openannotation/annotator/issues/408
Add polyfill for getSelection in IE8
For https://github.com/openannotation/annotator/issues/413
Re-adding checkbox tests.
Revert "Add polyfill for getSelection in IE8"

This reverts commit 6975d89da79208067524baeef66d8795e65487eb.
Partial revert of 277ac06a05989954e5df2e89ae658f4fef726e0c
Using cdnjs for test runner, adding es5shim and rangy.
Per @aron https://github.com/openannotation/annotator/issues/408
Adding IE shim for Sinon.
For https://github.com/openannotation/annotator/issues/414
Adding comment on plugin instantiation for tests.
Per @aron https://github.com/openannotation/annotator/pull/412#issuecomment-52942302
Merge pull request #412 from opengovfoundation/master

Fixes for Editor/Adder/Viewer for IE8