syntax: Drop support for shebangs ...

Shebangs are useful for writing scripts, but they assume an install of
NewLang separate from the application.

I don't plan to support that, only bundling of NewLang and its scripts.

syntax: Rename SyntaxLocation's column to offset ...

We don't know anything about columns or displaying the code points in
our source file, so be clear it's an offset and not a column.

syntax: Re-organize file

tests: syntax: Rename draw_token_location to draw_syntax_location

tests: tokenize: Move syntax tests to new file