Single character typo
Trims some dead tilde related code
Moves validating text after delimiter to Section

Section gets new method 'verify_delimiter', and sections call it
rather than rolling their own blocks of code.
Moves delimiter validation error messages to Section

Section delimiters changed to strings, with a Section method to turn
them into regexes (accepting an option of either :regex, or :before)
to turn them into a regular expression or a lookahead regular
expression that matches the spot before the delimiter, respectively.

Helps and Shops have their own implementation of self.delimiter,
because they have wonky delims (Helps needs to escape its $ character,
and Shops is just majorly messed up to begin with.)