Massive commit

*Everything* has changed, so bear with me while I dump it all into one commit.

## New:
- Syntax highlighting in code exports
- Autoprefixed CSS statements
- Justification, global alignment within parent ````div```` and overriding alignment per child ````div````

## Fixes & edits
- Actually do something with flex-size
- Move additional actions to dedicated sidebar. Click the ````div```` you want to edit first!