Revamped Deltastreamer (#93)

* Add analytics to site

* Fix ugly favicon

* New & Improved HoodieDeltaStreamer

 - Can incrementally consume from HDFS or Kafka, with exactly-once semantics!
 - Supports Json/Avro data, Source can also do custom things
 - Source is totally pluggable, via reflection
 - Key generation is pluggable, currently added SimpleKeyGenerator
 - Schema provider is pluggable, currently Filebased schemas
 - Configurable field to break ties during preCombine
 - Finally, can also plugin the HoodieRecordPayload, to get other merge types than overwriting
 - Handles efficient avro serialization in Spark

 Pending :
 - Rewriting of HiveIncrPullSource
 - Hive sync via hoodie-hive
 - Cleanup & tests

* Minor fixes from master rebase

* Implementation of HiveIncrPullSource
 - Copies commit by commit from source to target

* Adding TimestampBasedKeyGenerator
 - Supports unix time & date strings

hoodie-utilities/src/main/resources/delta-streamer-config/target.avsc

@@ -0,0 +1,29 @@
+{
+  "type" : "record",
+  "name" : "triprec",
+  "fields" : [ {
+    "name" : "_row_key",
+    "type" : "string"
+  }, {
+    "name" : "rider",
+    "type" : "string"
+  }, {
+    "name" : "driver",
+    "type" : "string"
+  }, {
+    "name" : "begin_lat",
+    "type" : "double"
+  }, {
+    "name" : "begin_lon",
+    "type" : "double"
+  }, {
+    "name" : "end_lat",
+    "type" : "double"
+  }, {
+    "name" : "end_lon",
+    "type" : "double"
+  }, {
+    "name" : "fare",
+    "type" : "double"
+  } ]
+}