A new lexer is noticeably faster and memory efficient
(although splitting a file to tokens is negligible in a whole pipeline).
But the purpose of rewriting lexer was not just to speed up,
but to allow writing code without spaces:
`2+2` is now 4, not a valid identifier as earlier.
The variety of symbols allowed in identifier has greatly reduced
and is now similar to other languages.
SrcLocation became 8 bytes on stack everywhere.
Command-line flags were also reworked:
- the input for Tolk compiler is only a single file now, it's parsed, and parsing continues while new #include are resolved
- flags like -A -P and so on are no more needed, actually