Added post_delete signal to remove the tenant schema. Just if auto_drop_schema is setted to True in the parent class.
Merge pull request #59 from jjimenezlopez/master

Added post_delete signal to remove the tenant schema (optional)
The signal must be called just by TenantMixin delete action
The drop_schema signal is being called even if we are deleting another object model (not a tenant). Added a check before try to drop the schema
Merge branch 'master' of https://github.com/jjimenezlopez/django-tenant-schemas
The drop_schema signal is being called even if we are deleting another object model (not a tenant). Added a check before try to drop the schema
Merge branch 'master' of git://github.com/jjimenezlopez/django-tenant-schemas into jjimenezlopez-master
now using a cleaner solution using sender
Merge branch 'jjimenezlopez-master'
add missing import