Add maybeCheckForSnapshotDependencies to build.gradle

to check for Snapshot dependencies in release builds.
Fix typo in XmlStringBuilder, it's not an Angel

s/rightAngelBracket/rightAngleBracket/
Merge branch 'master' into xep198

Conflicts:
	smack-core/src/main/java/org/jivesoftware/smack/packet/Bind.java
	smack-core/src/main/java/org/jivesoftware/smack/packet/Registration.java
rightAngleBracket