reindentation
added basic variable handling
added some lines before expression evaluation to make the generated asm valid for elf64
Now handles functions identifiers as well
Now flags input as wrong if the last char isn't a newline
Switched the call type of emit_ln() to &str reduce the nb of to_string() everywhere
Added assignments
Now allows identifiers bigger than 1 char, and nb longer than 1 digit
Added skipping of white-space