Merge pull request #16 from timlinux/develop

Small fixes for extent checking
Update to NESW assigning and validator.
Merge pull request #17 from timlinux/develop

Added missing static resources and migrations for tweaks to model change...
Merge pull request #18 from timlinux/develop

Fix hardcoded min max and default zoom
Merge pull request #19 from timlinux/develop

Fix validation of min and default zoom levels
Better populating fields.
Fix merged conflict.
Set default value for max_zoom.
Merge pull request #20 from ismailsunni/develop

Update populating field method
Update README.md
Merge remote-tracking branch 'upstream/develop' into develop
Remove cut and paste reference to inasafe