Bugfix & PG port

This release is mainly a maintenance release.

It enables SelvansGeo to work with a different PG port as the default one, and it checks that the MS connection is persistent.

Version 3.0.3

This is the first versionning release that we do from now on.

Final SelvansGeo release for QGIS 2.XX serie

This is the last release for the SelvansGeo plugin for QGIS 2.XX serie. There won't be any new functionnalities or patch applied to this. Users will be strongly encourage to migrate to QGIS 3.0 and SelvanGeo 3 in the beginning of 2018