Checklist for Polish and 100% done-ness

[felix91gr]

This issue pinpoints what's missing before I can consider this to be done as an example project for Pest and possibly Inkwell.

• Document required pre-installation of LLVM bits so that Inkwell works
• Refactor compiler, so that parsing, AST enrichment, semantic analysis and compiling are done in clearly separated ways.
• Localize language specifications
• Make Clippy pass all its default checks

[felix91gr]

Dependencies install: I had to install...

• gcc
• g++
• zlib1g-dev
• llvm7 (changed dependency to branch llvm7-0 for Inkwell)

[felix91gr]

Another item for the list: make Clippy pass all the checks. Just turned on Clippy and it's pretty amazing, it looks like it'll be a good learning experience :D