Watermarks can be centred, position set using gravity now
Gravity position for text overlays + some fixes
A bit about YAML in the README
Implement GCS storage; resolves #1
Better explanation of watermarks and text overlays in the README, added CHANGELOG
README fixes
Merge pull request #2 from hjr265/gcs-storage

Implement GCS storage; resolves #1
Updated README to talk about GCS
Added a link to changelog to the README
Improving parameter validation
Fixed file name clashes caused by different watermarks and text overlays
Updated CHANGELOG
v0.2