Release leveldb 1.11

Fixes issues
161
174
178

As well as the issue reported by edouarda14@gmail.com about
MissingSSTFile unit test failing on windows.
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Release leveldb 1.11

Conflicts:
	Makefile
	db/db_impl.cc
	db/db_test.cc