Multi-threaded compilation

[Enn3Developer]

At the current state, when called to compile an entire folder of Clue files, the compiler will compile the files one by one. That by itself isn't something bad, but for bigger projects it may take quite a lot of time to compile everything.
The proposal is as follows: change the behavior of compile_folder inside main.rs to add files in a queue to be processed by some compilation thread instead of compiling everything inside there.
This may even set a stepping stone for future work on multi-threading the compiler with fast compilations in mind (although as of now this is not really a necessity but with the planned features things may change)

[Maiori44]

This sounds good

[Maiori44]

This was added so it should be closed