Add results for D app compiled with LDC

[buggins]

DMD is a reference D compiler which provides only basic optimizations. For better results it's possible to use LLVM based LDC compiler. Please add D / LDC testing results to table.

Installation / downloads: LDC installation

Compiling & running:

     dub run --compiler=ldc2 --build=release

If ldc2 executable is not in path, use fully qualified path name.

[buggins]

UPD: I don't see any performance changes when test is built by ldc under windows. But selection of libevent configuration speeds up it twice.

dub.json

{
    "name": "vibedtest",
    "targetName": "vibedtest",
    "targetType": "executable",
    "targetPath": "bin",
    "dependencies": {
        "vibe-d": "~>0.8.1"
    },
    "subConfigurations": {
        "vibe-d": "libevent"
    },
    "versions": [
        "VibeDefaultMain", "VibeManualMemoryManagement"
    ]
}

[nuald]

Looks like macOS still has the performance issues, however I won't trust the averages anyway, and we can reiterate that later after I add the correct metrics and test on other platforms.