Executes a script that supports {{ expression }} and {{% code block }} syntax and returns a string result.

You can optionally pass in a pre-configured CSharpScriptExecution instance which allows setting references/namespaces and can capture error information.

Function returns null on error and scriptEngine.Error is set to true along with the error message and the generated code.

public string ExecuteScriptFile(string scriptFile, object model, 
			CSharpScriptExecution scriptEngine, string basePath)