Adding hoodie-spark to support Spark Datasource for Hoodie

- Write with COW/MOR paths work fully
 - Read with RO view works on both storages*
 - Incremental view supported on COW
 - Refactored out HoodieReadClient methods, to just contain key based access
 - HoodieDataSourceHelpers class can be now used to construct inputs to datasource
 - Tests in hoodie-client using new helpers and mechanisms
 - Basic tests around save modes & insert/upserts (more to follow)
 - Bumped up scala to 2.11, since 2.10 is deprecated & complains with scalatest
 - Updated documentation to describe usage
 - New sample app written using the DataSource API

hoodie-client/src/main/java/com/uber/hoodie/config/HoodieWriteConfig.java

@@ -31,6 +31,7 @@ import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Map;
 import java.util.Properties;
 
 /**
@@ -298,6 +299,10 @@ public class HoodieWriteConfig extends DefaultHoodieConfig {
             }
         }
 
+        public Builder withProps(Map kvprops) {
+            props.putAll(kvprops);
+            return this;
+        }
 
         public Builder withPath(String basePath) {
             props.setProperty(BASE_PATH_PROP, basePath);