Apply (modified) patch by Mwmaps

https://www.mediawiki.org/wiki/Extension_talk:Maps#Creating_maps_layers_table_..._Database.php:_Could_not_open_file._41933

https://github.com/JeroenDeDauw/Maps/issues/30
Update .travis.yml
Update TravisCI config for pgsql tests
Merge branch 'master' of github.com:JeroenDeDauw/Maps
Up TravisCI config
Update .travis.yml
Improve some i18n messages

Better phrasing for easier understanding and translation.
Merge pull request #40 from amire80/i18n

Improve some i18n messages
Update PHPUnit bootstrap
Merge branch 'master' of ssh://wmfgerrit/mediawiki/extensions/Maps