Remove language= parameter on sharedcontent.

This parameter is unneeded; better use:
`{% language "XX" %}{% sharedcontent ".." %}{% endlanguage %}`.
This works on a generic way, and gives consistent output without
confusion dual-language situations.

This partially reverts 4cbb9041c93e1d59f50038b65b30a2fe65d40b69
Fix all Django 1.7 migrations, had to set db_table manually.

Added migrations for remaining plugins too,
even though those packages may not be ready for 1.7 yet.
Remove Django 1.7 deprecation warnings
Add testapp migrations for Django 1.7
Release 1.0c3 to support newer package versions