[ADD] google_meeting module v.7.0

This PR contains the module **google_meeting** which provides a solution for synchronizing crm_meeting in Odoo v7.0 with Google Calendar.

I applied on the module https://github.com/solutions2use/google_api  developed by @solutions2use  a strong PEP8 cleanup and a bit of refactoring. I also renamed the module to google_meeting because it seemed more suitable.

See the description in the module manifest file for the installation notes.
can we add this scope as static variable at the beginning of the file?