Added support for 64-bit lmdb.dll
Implemented arch independence + nuspec

Relates #5
fixes permission denied issue on *nix

Relates #5
Updated lmdb submodule reference to 0.9.8 release
UnixAccessMode changed to public from internal

Also automatic changes to ripple.config
Modified rakefile and nuspec to produce package

Relates #5
Added fallback if no platform-specific lib

also fixed marshalling of mdb_version
Finished nuget package

Closes #5
Merge pull request #19 from ilyalukyanov/bittness-support

Final nuget package