Add Linux build/run script and .vscode dir

[adam820]

Hello! If you're interested, I have created a Linux-based build/run script and .vscode-directory directory for easier non-Windows setup. Since this was originally Windows-first this strives to not step on any toes; setting up for Linux requires a simple rename/delete of the existing .vscode folder and replacing it with .vscode-linux.

The script features some of the following:

• Based on the PS1 script, handles building and running, as well as locating a running Simulator and closing it before launch
• Colorized logging messages, controllable with NOCOLOR env var
• Warning dump if default package name found in source/pdxinfo

I've also updated the README to include instructions on setup. If you're not interested in this PR, feel free to close it and I will continue to maintain it on my fork/branch.

[Whitebrim]

Great work, I hope you'll maintain your linux part of this repo if there'll be any issues.