[SPARK-5310][Doc] Update SQL Programming Guide to include DataFrames.

Author: Reynold Xin <[email protected]>

Closes apache#4954 from rxin/df-docs and squashes the following commits:

c592c70 [Reynold Xin] [SPARK-5310][Doc] Update SQL Programming Guide to include DataFrames.

Author: rxin

docs/_layouts/global.html

@@ -71,7 +71,7 @@
                                 <li><a href="programming-guide.html">Spark Programming Guide</a></li>
                                 <li class="divider"></li>
                                 <li><a href="streaming-programming-guide.html">Spark Streaming</a></li>
-                                <li><a href="sql-programming-guide.html">Spark SQL</a></li>
+                                <li><a href="sql-programming-guide.html">DataFrames and SQL</a></li>
                                 <li><a href="mllib-guide.html">MLlib (Machine Learning)</a></li>
                                 <li><a href="graphx-programming-guide.html">GraphX (Graph Processing)</a></li>
                                 <li><a href="bagel-programming-guide.html">Bagel (Pregel on Spark)</a></li>

docs/index.md

@@ -74,7 +74,7 @@ options for deployment:
   in all supported languages (Scala, Java, Python)
 * Modules built on Spark:
   * [Spark Streaming](streaming-programming-guide.html): processing real-time data streams
-  * [Spark SQL](sql-programming-guide.html): support for structured data and relational queries
+  * [Spark SQL and DataFrames](sql-programming-guide.html): support for structured data and relational queries
   * [MLlib](mllib-guide.html): built-in machine learning library
   * [GraphX](graphx-programming-guide.html): Spark's new API for graph processing
   * [Bagel (Pregel on Spark)](bagel-programming-guide.html): older, simple graph processing model