Add security info and disclaimer
Add initial service discovery (XEP 30) support.

- Still needs caching and optimisation
Don't call the handler again in the except clause.

This was added earlier for debugging, removing it again now.
Better service discovery support

Features are saved to localStorage so that service discovery doesn't have to
happen during every request.
Merge branch 'master' into gh-pages

Conflicts:
	index.html