Update codequality/checkstyle.xml

Removing as it appears to no longer be available in the latest version of checkstyle that comes with gradle 1.4
Upgrading to Gradle 1.4
Switching to bintray for dependencies (same as Maven Central)
Move gradle-release dependency to bintray
Use newer version of license-gradle-plugin that fixes skipExistingHeaders field
Add sonatype snapshot repository
Using latest features of release plugin
Upgrading release process
Matching wrapper to 1.5
Automatically aggregate and publish docs (java,groovy,scala)
Make uploadMavenCentral task, that encompasses other tasks
avoiding some synchronization on combineLatest
Handle unavailable sonatype properties
Verify before we can't take it back, use preferredVersion variable
Passing status to Artifactory builds
Merge branch 'master' into combineLatest
Added support for the switch operation.
Reverted changes to junit and mockito imports in the Observable class.
Removed synchronized block as per RxJava guidelines (6.7).
Merge branch 'master' into combineLatest