Update tostring to inject xmlns definitions when needed.
Fixes for vCard avatar hash calculations and MUC considerations.
Ensure XMPPError.text is a string.
Put StringPrep exception handler with the right try block.
Add Google JID Domain Discovery plugin
Refactor Google GTalk extensions into a single meta plugin.
Tighten up session checks in XEP-0050 plugin.
Fix ping event issue.
Handle lang='*' in disco info
Add proper XEP-0071 plugin.
Add Google plugins to setup.py
Get tests to pass again.

Re-add old gmail_notify plugin for now.
Fix HTML-IM lang support.
Add option to XEP-0077 plugin to force registration attempts.
Enable force_registration in the register account example.
Merge branch 'develop'
Merge branch 'xep_0077'
Tidy up a bit
Remove old_* plugins.
Ensure gmail last result time and tid are always updated.