Release v3.21.1.0

• Added support for C#6 syntax to Mono evaluator.
• Issue #33: Cleanup routine throws ArgumentException
• Added extending environment variables in all parameters passed from command line.
• Improved API XML documentation to address some of the Issue #26 concerns.
• User experience improvements triggered by intensive Linux testing
• Various improvements for stdout help.
• Improved reliability of Auto-class decorating algorithm
• Added support for referencing NuGet packages from the script being executed on Linux
• Added -noconfig:print and -precompiler:print options for printing the content in stdout.
• Extended Python-like "print" functionality:
• Added params concatenation: print(obj1, obj2,...objN)
• Added pringf for params formatting: printf("Now: {0}", DateTime.Now)
• added support for collections: print(Directory.GetFiles(".", "*"))
• Added decorateAutoClassAsCS6 setting for injection using static dbg; into auto-class decoration.
• Issue#32: Inconsistent time stamp (.dll -vs- .pdb) when using CSScript.CompileFile() with 'debugBuild = true'
• Added support for output file in //css_res.
• Implemented supressing elevation during syntax checking (with -check) for the scripts with //css_pre elevate directive.
• Improved settings file parsing to avoid throwing handled exceptions.
• Added support for CSS_RESGEN environment variable for embedding resources with //css_res.
• Code cleanup
• Various obsolete code marked as error triggering.
• Removed old obsolete ResolveSourceFileHandler delegate and MonoEvaluator.Configuration member.
• Staretd removal of obsolete .NET1.1 code (conditional compiler directives).