fix ReferenceError in browsers

Signed-off-by: Dmitry Kryuchkov <xelibrion@gmail.com>
Update README.md

Updating parallel route README to use proper ui-sref links
Added egghead.io intro video to Learn section
Small fix example in README.md
Added innerText shim for Firefox compatibility

The tests fail on Firefox as firefox uses W3C-compliant textContent

Update test to use the shim