* Update meshoptimizer to 0.16

* Update CI baseline

* Address PR feedback

* Update git-tree hash

Co-authored-by: chausner <chausner@users.noreply.github.com>
Co-authored-by: Billy Robert O'Neal III <bion@microsoft.com>

```
function Convert-Control {
    Param($full)
    .\vcpkg.exe format-manifest $full
    $root = $full.Substring(0, $full.Length - 7) # CONTROL
    $new = $root + 'vcpkg.json'
    $content = Get-Content -Raw $new
    $asJson = ConvertFrom-Json $content -AsHashtable -Depth 100
    $oldVersion = $asJson['port-version']
    if ($null -eq $oldVersion) {
        $oldVersionFull = $asJson['version-string']
        Write-Host "Got version $oldVersionFull"
        $match = [System.Text.RegularExpressions.Regex]::Match($oldVersionFull, '^(.+)-(\d+)$')
        if ($match.Success -and -not [System.Text.RegularExpressions.Regex]::IsMatch($oldVersionFull, '^\d\d\d\d-\d\d-\d\d$')) {
            $newFullVersion = [string]$match.Groups[1].Value
            $oldVersion = [int]$match.Groups[2].Value
            Write-Host "newFullVersion $newFullVersion oldVersion $oldVersion"
            $newVersion = $oldVersion + 1
            $asJson['version-string'] = $newFullVersion
            Write-Host "Previous version for $full extracted from version field -- setting version-string $newFullVersion and port-version $newVersion"
        } else {
            Write-Host "No previous version for $full -- setting 1"
            $newVersion = 1
        }
    } else {
        $newVersion = [int]$oldVersion + 1
        Write-Host "New version for $full : $newVersion"
    }

    $asJson['port-version'] = $newVersion

    $content = ConvertTo-Json $asJson -Depth 100
    Set-Content -Path $new -Value $content
    .\vcpkg.exe format-manifest $new
}

Get-ChildItem ports\CONTROL -Recurse | Foreach-Object {
    Convert-Control $_.FullName
}

git commit -am "this message"
.\vcpkg.exe x-add-version -all
git commit -a --amend
```

* [magnum] Improve maintainability of feature to cmake flag conversion

* [magnum] Ignore features not supported on current platform

Allows `vcpkg install magnum[*]` on any platform.

Signed-off-by: Squareys <squareys@googlemail.com>

* [magnum] Add cglcontext and windowlesscglapplication features

* docs: Update valid VCPKG_CMAKE_SYSTEM_NAME values

Signed-off-by: Squareys <squareys@googlemail.com>

* [magnum-plugins] Replace deprecated basisu with archive download

Signed-off-by: Squareys <squareys@googlemail.com>

* [magnum-plugins] Add meshoptimizersceneconverter feature

Signed-off-by: Squareys <squareys@googlemail.com>

* [magnum-plugins] Also use vcpkg_check_features

Analog to magnum port.

Signed-off-by: Squareys <squareys@googlemail.com>

* [corrade,magnum,*-plugins,*-extras,*-integration] Update to v2020.06

Signed-off-by: Squareys <squareys@googlemail.com>

* [meshoptimizer] Add initial port

Signed-off-by: Squareys <squareys@googlemail.com>

* [magnum-plugins] Replace meshoptimizer download with feature dependency

Signed-off-by: Squareys <squareys@googlemail.com>

* [corrade,magnum-*] Fix license installation command

Signed-off-by: Squareys <squareys@googlemail.com>

* [meshoptimizer] Use vcpkg_fixup_cmake_targets

Co-authored-by: Robert Schumacher <roschuma@microsoft.com>