Currently I'm relying on JavaScript's semantics
around truthiness. I think I'm going to retain
that ease of use (i.e. `(if list #t #f)` should
return true if the list has more than 0 elements,
etc) but I want to specify that behavior myself.

Just numbers and strings for now

It's a little hacky and not very clean but it's
working for now.

What was happening was that spaces were allowed in
all literals to account for quoted strings, but
this meant that two identifiers in a row would get
parsed as a single literal. This commit sets a
flag to allow whitespace in literals when a quote
is encountered and then unsets that flag at the
next quote.

No variables or conditionals or anything yet, just
the basic ability to turn s-expressions into HTML.