To use ZptSharp from a command line, a standalone app must be created

[craigfowler]

This is to create a command line renderer app. It must support both .NET framework and dotnet core. This is functionality which has yet to be carried-forward from the v1.x branch. It also had some unit tests which should be reviewed.

[craigfowler]

If I wish to multi-target this (to work on either .NET Framework or .NET Core) then it's going to need some code differences.

On dotnet core, I have Generic Host available as a technique, but on just .NET Framework I will likely need to use the self-hosting facility written in #265

[craigfowler]

I would like to be able to support plugins, in order to activate document providers and/or expression types. Here's some info on how to do that for .NET Core 3:

I have chosen not to use plugins at this time. I will ship the app with all of the standard expression types and document providers.

info about plugins for .NET Core 3

https://docs.microsoft.com/en-us/dotnet/core/tutorials/creating-app-with-plugin-support

[craigfowler]

Planned command-line options:

• The main argument (without a named option) indicates the root path for the file search. It's mandatory.
• --include or -i adds a file-search pattern to be included
  • If omitted then the pattern * is used, to non-recursively handle all files in the directory.
• --exclude or -x adds a file-search pattern to be excluded
  • If omitted then there are no expressions.
• --model or -m points to a JSON file containing the model
  • If omitted then the model is null.
• --keywords or -k is a list of key/value pairs
  • If omitted then there are no keyword options defined.
• --extension or -e is a file extension for the rendered output
  • If omitted then the extension is not changed.
• --anglesharp or -s uses the AngleSharp renderer instead of HAP, for HTML files
• --annotate or -a enables source annotation