Add more (infix) operators

[b-studios]

This PR adds a few more infix operators. This is mostly just lexing and parsing so doesn't come with a lot of conceptual cost for the implementation.

A few things are not clear / implemented:

• we should name things consistently (I actually would like to rename infixAdd to InfixPlus, but this will break a lot of things)
• is this slowing down the parser? (for precedence it is now deeply nested)
• is the precedence ok?
• should pipe left and right be by-name? This might open up some cool usages.
• right now the new tokens are added as one batch, we might want to clean them up by sorting them somehow
• I didn't add a === b and a !== b since the tokens === are already used to represent ==, ahhh.