TAJO-1123: Use Fragment instead of FileFragment.

Closes #207
Merge branch 'hbase_storage' of https://git-wip-us.apache.org/repos/asf/tajo into TAJO-1127

Conflicts:
	tajo-common/src/main/java/org/apache/tajo/TajoConstants.java
	tajo-core/src/main/java/org/apache/tajo/engine/planner/PhysicalPlannerImpl.java
	tajo-core/src/main/java/org/apache/tajo/engine/planner/physical/SeqScanExec.java
	tajo-core/src/main/java/org/apache/tajo/master/GlobalEngine.java
	tajo-core/src/main/java/org/apache/tajo/master/LazyTaskScheduler.java
	tajo-core/src/main/java/org/apache/tajo/master/NonForwardQueryResultScanner.java
	tajo-core/src/main/java/org/apache/tajo/master/querymaster/Repartitioner.java
	tajo-core/src/main/java/org/apache/tajo/master/querymaster/SubQuery.java
	tajo-storage/src/main/java/org/apache/tajo/storage/FileStorageManager.java
	tajo-storage/src/main/java/org/apache/tajo/storage/MergeScanner.java
	tajo-storage/src/main/java/org/apache/tajo/storage/StorageManager.java