Should be able to capture screenshot

Getting the following error

        Failed Step: Vowels in English language are "aeiou".
        Specification: specs\example.spec:11
        Error Message: The system cannot find the file specified
        Stacktrace:
           at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)
           at Gauge.CSharp.Lib.DefaultScreenGrabber.TakeScreenShot()
           at Gauge.CSharp.Lib.GaugeScreenshots.Capture()
           at one.StepImplementation.SetLanguageVowels(String vowelString) in ...\one\StepImplementation.cs:line 17

Steps to replicate

Create a gauge-csharp project

Add GaugeScreenshots.Capture() to the step

    [Step("Vowels in English language are <vowelString>.")]
    public void SetLanguageVowels(string vowelString)
    {
        Gauge.CSharp.Lib.GaugeScreenshots.Capture();

        _vowels = new HashSet<char>();
        foreach (var c in vowelString)
        {
            _vowels.Add(c);
        }
    }

Version

Gauge version: 1.0.1.nightly-2018-07-18
Commit Hash: e62f840

Plugins
-------
csharp (0.10.5.nightly-2018-07-19)
html-report (4.0.5.nightly-2018-07-11)

Blocks #137

getgauge / gauge-csharp

Should be able to capture screenshot #141