Adds a working example app

The original example app was missing some files
and did not run. This fixes it up. I pushed it to a
stackato VPS and purchased it on Marketplace Dev to test
it out.

After this fix, you'll want to run npm publish so that
the example dir in the receiptverifier package gets updated.
Merge pull request #12 from kumar303/example-fix
Fix a bunch of little jshint warnings
Added mockMozApps._clear() and fixed some jshint stuff
Add requireSameOrigin parameter to verifier.
Make verify domain check automatic (not an option).  Change to a subdomain check instead of a same-origin check.
don't allow test-receipts by default
Merge pull request #13 from andymckay/master

don't allow test-receipt by default
fix backtick
added receipt type links to readme
Merge pull request #14 from nickdesaulniers/readme
small typo in readme
Merge pull request #15 from nickdesaulniers/readme
small correction to readme and typsAllowed
Merge pull request #16 from nickdesaulniers/readme
add in product url checks (bug 867282)
Merge pull request #18 from andymckay/url-checks

add in product url checks (bug 867282)
split out the ui from the lib (bug 902946)
Merge pull request #19 from andymckay/902946

split out the ui from the lib (bug 902946)