More intuitive name
Preprocessor returns Seq[Result[LogicalLine]] instead of Result[Seq[LogicalLine]], so that we can emit both the preprocessor error and later errors
Newline node is obsolete
MathCompiler can report up to one error per logical line (though InlineParser won't pass them on)
Update documentation
Code generator function generates one node at a time, in preparation to convert to Result/Either
Correctly report physical line numbers in `Failure`s
Bugfix with previous commit
MathExpr nodes retain position information, at least relative to their logical line
I think I'm going to have to give up on satisfying IntelliJ