Added composer.json
Added travis support
Added README with build status
Fixed travis.yml paths
More graceful handling of missing GET data in ModelAdmin

See https://github.com/silverstripe/silverstripe-cms/pull/253
BUG Consistently use FormResponse in CMS JavaScript (fixes #8036)

Regression caused by a security fix in 9bf3ae9a190
Fixed composer.json dependencies
Merge remote-tracking branch 'origin/2.4' into 3.0