* Rename IndexPathMap to IndexNamespace
 * Test the case there is a leveldb failure when inserting an element.
 * Added virtual constructor to interface
Merge branch 'master' into index_namespace
 * Added masterd.thrift to define internal data structures
 * Use MockLevelDBStore in index_namespace_test
 + Added a test case to load index namespace from disk
Merge pull request #12 from vsfs/index_namespace

Rename IndexPathMap to IndexNamespace