Refactoring on help display, fix bug of key_fields is None not displaying
Define DEFAULTS to be able to access them after init
To avoid failure after configuration file loading, we put to default any None value for directives
Clearer error message when poor join_info
Minor refactoring
Set join info for ori_por, field country_code
Remove previous join implementation on load
Rename ext_g in join_b for join base
Join clause implementation, lazy version on get call
Give access to getLocation in external base with special ext_field value __loc__
Adding join_info on tvl_por_list
Implementation of multiple join of multiple fields
Fix bug of cluttered join_info
Additional tests for join_fields len in configuration