Merge pull request #5 from Junkern/master

Did some work on HBase scanTable. Some things to discuss about
Renamed "Configurator" class to "NoSQLMiddleware"
Deleted class "UnifyingMiddleware" and shifted methods to "NoSQLMiddleware" class.
Refactored.
Changed name from "Operator" to "ComparisonOperator".
Extended the Filter class to be applicable for Hbase, too.
Refactored.
Begin of refactoring of the JUnit tests
Adding a column in Cassandra also creates a new index
Deprecated getRowsByKeys
Marked getRowsByKeys as deprecated
A handler for a database has to implement the MiddlewareInterface
Refactored.
Deleted QueryHandler.
Refactored.
Tests are successful for Cassandra, DynamoDb and Hypertable.
Hbase test also works now.
Added try-catch to dynamoDb deleteTables. Tests are successful again.
Bugfix
deleted system.out.println
Merge branch 'master' of https://github.com/B3nRa/ColumnStoreUnifier
added abstract.
Bugfix in Cassandra for LT, GT, GE, LE when no EQ is existent in the
query