Fix filename and rule name for Appcache/5apps(.com)

While browsing our website I noticed that HTTPS Everywhere had a typo in
the site name. As our products and websites are known under the name
5apps, rather than the formal company name Appcache Ltd, I renamed all
of it to 5apps instead of just fixing the typo.
Merge pull request #751 from 5apps/master

Fix filename and rule name for Appcache/5apps(.com)