Update to KeyStorage

-KeyStorage is completed, but may require further
 updating to be consistent with future
 implementations of the classes that it utilizes.
DiskSpace & LinearMemoryDatabase

- Initialized classes for DiskSpace and
  LinearFileDatabase.
- Reverted LinearMemoryDatabase to
  original state.
Merge branch 'master' of https://github.com/patrick-motard/SearchEngineV1.git