Release LevelDB 1.14

Fix issues 200, 201

Also,
* Fix link to bigtable paper in docs.
* New sstables will have the file extension .ldb. .sst files will
continue to be recognized.
* When building for iOS, use xcrun to execute the compiler. This may
affect issue 177.
Cleanup files not part of the distribution
Merge commit '0b9a89f40efdd143fa1426e7d5cd997f67ba6361' into merge/upstream-1.14

* commit '0b9a89f40efdd143fa1426e7d5cd997f67ba6361':
  Release LevelDB 1.14

Conflicts:
	AUTHORS
	Makefile
	db/db_iter.cc
	issues/issue200_test.cc
Keep *.sst as default, support *.ldb as needed
Merge branch 'merge/upstream-1.14'

* merge/upstream-1.14:
  Keep *.sst as default, support *.ldb as needed
  Release LevelDB 1.14