Fix Tests (#42)

* Changed SPM to an active-low reset design and updated tests accordingly
* Fixed bug where newer versions of IcarusVerilog decided to add fluff to the output, breaking it
* Switched from https://github.com/lukaskubanek/OrderedDictionary to [Swift Collections](https://github.com/apple/swift-collections)

Explicit Muxes in Scan-chain and SCL Configuration YAMLs (#40)

* Created YAML configuration file for supported SCLs with the ability to define:
  * D-flipflops and their D/Q portnames (if for some godforsaken reason the ports are not named D and Q)
  * Optionally, a multiplexer to use for scan-chain stitching
    * If the multiplexer exists, it takes priority, otherwise, a ternary operation is used
* Updated Swift requirement to 5.4+
* Updated macOS requirement to 11+
* Ran [SwiftFormat](https://github.com/nicklockwood/SwiftFormat)'s default ruleset on all files.

venvs + Update Documentation (#36)

+ Use venv for testing and the installer
+ Main function now supports the variable `PYTHONPATH`, which if it does not exist, it attempts to extract `sys.path` from the Python binary in `PATH` 
~ Update install script to create a release binary and use N threads
~ Fix portions of README that were out of date (thanks @ekliptik!)
- Drop support for Ubuntu 18.04 installation (AppImage should still work)

Fix smoke test

Provide AppImages for Linux (amd64) (#29)

+ Add capability to build an AppImage based on the Docker file, which can be download on any Linux distribution with a glibc greater than or equal to CentOS 7.
+ Add a smoke-test script to the Docker image and the AppImage (to ensure everything is okay)
+ Added Python/Pyverilog version checkers
~ Greatly reduced Docker image size by using a multi-layer image
~ Changed CLI slightly so output files have full names and not prefices
- Removed Jinja2 from dependencies