Small build fix
Fix bug that would cause import failures in Intellij

https://github.com/GoogleCloudPlatform/gradle-appengine-plugin/issues/124
We don't need the idea plugin anymore as the Gradle import functionality
in intellij reads state from gradle directly.
Add in check for Gradle Version >= 2.1
Add Update Dispatch Task
Release 1.9.13
Update README.md
Fix logs severity check: don't evaluate 0 as false
Add includeAll option in logs task
Update Cloud Platform Logo
Update release notes for 1.9.14 release, and update versions to use 1.9.14 appengine sdk