Google Contacts 0.5.50b6

I've uploaded Google Contacts 0.5.50b6. It fixes a problem in a batch synchronization and add new option to a group mapping functionality. You can choose one of two delete operation when you enables the group mapping: delete from Google and delete from the mapped group.

In addition to that, I decided to use Javascript 1.7 and its yield statement in the beta. I enables the add-on to release CPU regularly. It makes synchronizing time a little bit long but it reduces freezing of GUI.

After the b6 release, I'm going to localize the addon and submit to BabelZilla. Please keep watching BabelZilla and translate new strings when it is available there. I'll start to work for Thunderbird3 add-ons after official release of v0.5.50.