Allow an OAuth process to specify a callback URI
Enable use of callback with Twitter

Since the current API tokens for Twitter do not allow the use of a
callback, new ones have been used here. We can change that back once the
settings for the old ones have been updated.
Reorganize strings for oauth authentications
Merge branch 'oauth-inband' into upstream

Conflicts:
	main/src/cgeo/geocaching/twitter/TwitterAuthorizationActivity.java
refactoring: more annotations