fix invalid namespace
Merge branch 'csanquer-fix-336'
Merge branch 'master' into develop
Add test for #336
Update changelog
Merge branch 'master' into develop
Fix version number
Merge branch 'master' into develop
Improve exceptions in Gd driver's open()

- RuntimeException more suitable (and consistent with other drivers)
- Change message as file existence is checked beforehand in checkPath() (refs #326)