The variable names and comments around the code refer to the main thread
as the "tokenizer" and the parser thread as the "html tokenizer". This
confuses me every time I look at the code, because both tokenize html
and neither can do it without the other.
I've renamed things to be a bit more clear, mostly referring to things
as the "main thread" and the "parser thread".
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>