CircleCI build on release branches

[otormaigh]

All release branches should run a check on code commited to them like master. Can add a wildcard to the relevant step to catch the release branches. Will need to update naming conventions on release branches though.

• Update RELEASING.md branch naming to release-{versionName}
• Add check step
• Add a dry-run publish step
  • I don't this is possible through the plugin, might be enough to do a release build just to be sure it runs OK?

[otormaigh]

Updated RELEASING.md and added check step to release-* branches.

Also added a gradle task to help with preparing a new release see : d1248f9