Adding range based pruning to bloom index

- keys compared lexicographically using String::compareTo
 - Range metadata additionally written into parquet file footers
 - Trim fat & few optimizations to speed up indexing
 - Add param to control whether input shall be cached, to speed up lookup
 - Add param to turn on/off range pruning
 - Auto compute of parallelism now simply factors in amount of comparisons done
 - More accurate parallelism computation when range pruning is on
 - tests added & hardened, docs updated

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

@@ -203,6 +203,14 @@ public class HoodieWriteConfig extends DefaultHoodieConfig {
         return Integer.parseInt(props.getProperty(HoodieIndexConfig.BLOOM_INDEX_PARALLELISM_PROP));
     }
 
+    public boolean getBloomIndexPruneByRanges() {
+        return Boolean.parseBoolean(props.getProperty(HoodieIndexConfig.BLOOM_INDEX_PRUNE_BY_RANGES_PROP));
+    }
+
+    public boolean getBloomIndexUseCaching() {
+        return Boolean.parseBoolean(props.getProperty(HoodieIndexConfig.BLOOM_INDEX_USE_CACHING_PROP));
+    }
+
     public int getNumBucketsPerPartition() {
         return Integer.parseInt(props.getProperty(HoodieIndexConfig.BUCKETED_INDEX_NUM_BUCKETS_PROP));
     }