Merge features added for Extended FEC into standard FEC
This also includes some minor improvements in standard FEC implementation/bt5 and Unit Tests. All ERP5 Unit Tests pass: https://nexedi.erp5.net/test_result_module/20180507-5DA5AC76
This also includes some minor improvements in standard FEC implementation/bt5 and Unit Tests. All ERP5 Unit Tests pass: https://nexedi.erp5.net/test_result_module/20180507-5DA5AC76