Fix crash when image is not found

• Now embeds externally referenced png images in the HTML as base64

If running in a Bamboo context (environment variables are defined and available) then the report includes:

• Bamboo branch name
• Bamboo build number
• Link to results page URL

Also now sorts by feature name in each scenario and highlights Skipped features

• Depends on FluentCommandLineParser-netstandard nuget package
• Added option --title argument
• Usage format is now: PS> dotnet .\TrxReporter.dll --input path-to-trx [--output output-path] [--title title]

• Simplified style sheets and scripts
• New simpler styling

Simplify error HTML

Flatten the output to expose scenarios per each feature

Target .NET Core 2.2
Simpler layout
Handles output from SpecFlow showing gherkin and captured images
Click images to show them zoomed in modal dialog