Prevent concurrent exports to run on the same binding record by acquiring a lock on the binding record before exporting it
Add a 'export_dependency' helper method in the Exporter to ease the export of dependencies
Fix pep8
add binding_extra_vals param in _export_dependency method
Change condition to export record in _export_dependency
Merge pull request #33 from guewen/7.0-export-dependency+lock

Add mechanisms for the export of records