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
Reimplementation of Concat, improved handling of Observable<Observable<T>>.

The old version required all of the Observable<T>s to be generated and buffered
before the concat could begin.  If the outer Observable was asynchronous, items
could be dropped (test added).  The new version passes the test, and does the
best job I could (after examining several possible strategies) of achieving
clear and consistent semantics in accordance with the principle of least
surprise.
Use newer version of license-gradle-plugin that fixes skipExistingHeaders field
Add sonatype snapshot repository
Using latest features of release plugin
Incorporate review feedback.

Also restore the errant change to settings.gradle.
Merge branch 'upstream' into issue202
Rename Subject to PublishSubject
Introduce Subject as analogue to RX ISubject
Implement RepeatSubject
Extract UnsubscribeTester to top level
Beef up UnsubscribeTester
Beef up UnsubscribeTester some more
Add unit tests to PublishSubject
Merge branch 'master' into replay

Conflicts:
	rxjava-core/src/main/java/rx/operators/OperationTake.java
Resolve merge conflicts
Upgrading release process