Refactor parser grammar to not require the array index so often
Change a SELECT query so the from node is optional
Move BNF reference to the top of the file
Fix parser to use the correct value
Add operator precedence and associativity to the parser
Add parenthesis to binary infix operators

* Add comments explaining the algorithm I will used to properly
  parenthesize the operators based on their precedence rules
  compared to the parent, as well as associativity compared to their
  position relative to their siblings.