Added PigLatin language identification.

Updated languages.yml to associate *.pig files with PigLatin.
Added pig script example to samples/.
Updated the samples.json with to account for new sample.

samples/PigLatin/example.pig

@@ -0,0 +1,10 @@
+/**
+ * sample.pig
+ */
+
+REGISTER $SOME_JAR;
+
+A = LOAD 'person' USING PigStorage() AS (name:chararray, age:int); -- Load person
+B = FOREACH A generate name;
+DUMP B;
+