I installed your plugin on WP 3.6 and it runs very smoothly with my four languages. There is only one issue I can't solve:
The main site example.com wrongly links to example.com/#!/fr, example.com/#!/de etc. Once I corrected the URL manually to example.com/fr, example.com/de etc., everything works again and the links bring me to the correct pages example.com, example.com/fr, example.com/de etc.
Do you know how to fix this? Was it a mistake to first activate the plugin for the sub-domains and then in the end for the main site?
Many thanks for your help!