Added es5-shim.js and its minified version.

From kriskowal/es5-shim@e5e3fe995f77ddf3350431c464423ddcab49d9f0.
Add IE8 support to fakeissuer.

Also dynamically generate the Issuer JS API URL, rather than hard-coding
it to localhost.
Add es5-shim script to layout.html and badge-accept.html.
Fixes to issuer.js for modalless issuer API flow.

Doing this with issuer.js is a bit challenging because we don't want
to modify the prototypes of the client page, so we can't just add an
es5 shim.
nunjucks 0.1.10 seems IE8 compatible
Merge pull request #956 from stenington/ie8-fixes-spike-2

#turkey Reviving IE8 fixes