Patch gora-cassandra to work with Nutch 2.1

This submission fixes the following issues:

GORA-103
GORA-169
GORA-182
GORA-196
GORA-197
GORA-210
GORA-211

gora-cassandra/pom.xml
gora-cassandra/src/main/java/org/apache/gora/cassandra/query/CassandraQuery.java
gora-cassandra/src/main/java/org/apache/gora/cassandra/query/CassandraResult.java
gora-cassandra/src/main/java/org/apache/gora/cassandra/store/CassandraClient.java
gora-cassandra/src/main/java/org/apache/gora/cassandra/store/CassandraMapping.java
gora-cassandra/src/main/java/org/apache/gora/cassandra/store/CassandraMappingManager.java
gora-cassandra/src/main/java/org/apache/gora/cassandra/store/CassandraStore.java
gora-cassandra/src/main/java/org/apache/gora/cassandra/store/HectorUtils.java

Synced with https://github.com/apache/gora/commits/trunk @ 390f8694eb890bc063fb99ed5de8feadf65ff113