added utility to dump leveldb files
Fix corruption bug found and analyzed by dhruba@gmail.com

https://groups.google.com/d/msg/leveldb/Kc9JxuIUu5A/9P0N9RL4ar8J
Make DB::Open fail if sst files are missing.

Also, cleanup for Clang's -Wimplicit-fallthrough warning.
Release leveldb 1.10

Fixes issues
147 - thanks feniksgordonfreeman
153
156
166

Additionally,
* Remove calls to exit(1).
* Fix unused-variable warnings from clang.
* Fix possible overflow error related to num_restart value >= (2^32/4).
* Add leveldbutil to .gitignore.
* Add better log messages when Write is stalled on a compaction.
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.
Release leveldb 1.12

Non-functional changes only:
1) Add Kevin Regan to the AUTHORS file
2) Add standard license header to issues/issue178_test.cc
Remove Snappy support
Native Windows LevelDB port

Import native Windows LevelDB port by Hiram Chirino.

Extracted from from https://github.com/chirino/leveldb.git using
git diff dd0d562..aea83b7
Pre-Vista leveldb::port::InitOnce implementation
Mingw support for Windows LevelDB port
Port leveldb to MinGW32

Several changes to make the native windows leveldb code compile
with mingw32 and run on 32-bit Windows:
* Remove -std=c++0x dependency (modified code to use NULL instead of
  nullptr)
* Link with -lshlwapi
* Only #define snprintf/etc if compiling with Visual Studio
* Do not link against DbgHelp.lib (wrote a CreateDir instead of using
  DbgHelp's MakeSureDirectoryPathExists
* Define WINVER=0x0500 so MinGW32 can use the 64-bit-filesystem Windows
  api calls
* Define __USE_MINGW_ANSI_STDIO=1 to use MinGW's printf (which supports
  %ll)

I also cleaned up makefile.mingw, assuming that dependencies would be in
the standard /usr/local/{include,lib} by default but allowing overriding
with make DEPSDIR=... etc
Print actual Win32 error that occurred on file creation failure.
Checking whether closing succeeds
Allow files to be opened for reading multiple times
CondVar::SignalAll was broken, leading to deadlocks on Windows builds.
http://code.google.com/p/leveldb/issues/detail?id=149
Added GNU/kFreeBSD kernel name (TARGET_OS)

uname -s returns "GNU/kFreeBSD" on Debian GNU/kFreeBSD port. See http://www.debian.org/ports/kfreebsd-gnu/