* Update the project to Swift 5.4
- Splash now uses the Swift 5.4 toolchain.
- Since Swift 5.4 now enables automatic test discovery on all supported
platforms, all of the infrastructure that was previously used to maintain
Linux unit testing compatibility has now been removed.
* Remove LinuxMain.swift
This change adds a new command line tool to the Splash family:
`SplashMarkdown`.
It’s an adapted version of the tool that I’ve been using for months to
publish every article on Swift by Sundell, and works by replacing all
code blocks within a Markdown file.
Adding this will hopefully make Splash even easier to use, without the
need for writing custom tooling, or to manually replace each code block
within a Markdown file with a “splashed” version.
This change adds SwiftLint to the project. For now, the rules are tweaked
to match the current state of the code base — but will over time be changed
back to their defaults in several cases.
Some smaller changes (mostly related to code style) were applied to the
project to remove all warnings.