mqttinputdstream for mqttstreaming adapter
added mqtt adapter
added mqtt adapter library dependencies
added mqtt adapter wordcount example
add maven dependencies for mqtt
add maven dependencies for mqtt
remove unused dependency
remove unused dependency
modify code, use Spark Logging Class
Update MQTTInputDStream.scala
Update MQTTWordCount.scala
Updated TransformDStream to allow n-ary DStream transform. Added transformWith, leftOuterJoin and rightOuterJoin operations to DStream for Scala and Java APIs. Also added n-ary union and n-ary transform operations to StreamingContext for Scala and Java APIs.
Show "GETTING_RESULTS" state in UI.

This commit adds a set of calls using the SparkListener interface
that indicate when a task is remotely fetching results, so that
we can display this (potentially time-consuming) phase of execution
to users through the UI.
Update MQTTWordCount.scala
Update MQTTWordCount.scala
Add classmethod to SparkContext to set system properties.

Add a new classmethod to SparkContext to set system properties like is
possible in Scala/Java. Unlike the Java/Scala implementations, there's
no access to System until the JVM bridge is created. Since
SparkContext handles that, move the initialization of the JVM
connection to a separate classmethod that can safely be called
repeatedly as long as the same instance (or no instance) is provided.
Shorten GETTING_RESULT to GET_RESULT
Pass self to SparkContext._ensure_initialized.

The constructor for SparkContext should pass in self so that we track
the current context and produce errors if another one is created. Add
a doctest to make sure creating multiple contexts triggers the
exception.
Add notes to python documentation about using SparkContext.setSystemProperty.
Merge pull request #97 from ewencp/pyspark-system-properties

Add classmethod to SparkContext to set system properties.

Add a new classmethod to SparkContext to set system properties like is
possible in Scala/Java. Unlike the Java/Scala implementations, there's
no access to System until the JVM bridge is created. Since
SparkContext handles that, move the initialization of the JVM
connection to a separate classmethod that can safely be called
repeatedly as long as the same instance (or no instance) is provided.