May Fix #272. Enables TG apps to run in terminal StatusLine

[tig]

Fixes

• Partially Fixes Make non-fullscreen apps possible #272

Background

See: https://github.com/mintty/mintty/blob/master/wiki/CtrlSeqs.md#status-line--area

It should be possible to add support for this. Add a Application.RunAsTerminalStatusLine and Application.TerminalStatusLineHeight. When set, upon Init we would emit #"^[[2;{Application.TerminalStatusLineHeight}$~". On Shutdown, we would emit ^[[0$~.

I believe this would automatically constrain the TUI app to the bottom TerminalStatusLineHeight of the terminal.

Proposed Changes/Todos

• Add appropriate CSIs
• Experiment with WindowsDriver

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui - if you use Visual Studio, hit CTRL-K-D to automatically reformat your files before committing.
• My code follows the Terminal.Gui library design guidelines
• I ran dotnet test before commit
• I have made corresponding changes to the API documentation (using /// style comments)
• My changes generate no new warnings
• I have checked my code and corrected any poor grammar or misspellings
• I conducted basic QA to assure all features are working