Coding standard

@timlinux: just an example of not importing safe from safe_qgis. Is this the correct way? So, we need to also delete this https://github.com/AIFDR/inasafe/blob/develop/safe_qgis/impact_statistics/postprocessor_manager.py#L27 and make those functions (unhumanize_number, format_int) available from safe.api?