Fixes #198

Co-authored-by: Ben Kurtovic <ben.kurtovic@gmail.com>

Also removed the max cycles stop-gap, allowing much more complex pages
to be parsed quickly without losing nodes at the end

Also fixes #65, fixes #102, fixes #165, fixes #183
Also fixes #81 (Rafael Nadal parsing bug)
Also fixes #53, fixes #58, fixes #88, fixes #152 (duplicate issues)

Also add a couple for templates and one for integration.

Mostly by @gdooms, with tweaks.

- Stop parsing new templates if the template depth gets above
  MAX_DEPTH (40) or if we've already tried to parse over MAX_CYCLES
  (100,000) templates.
- Add two tests to ensure recursion works somewhat correctly.
- Fix parsing the string "{{" with the Python tokenizer; add a test.

- Newlines are now allowed in template param names.
- Changes also affect handling of arguments like {{{foo}}}.
- Update unit tests: remove some unnecessary ones, and add some to cover the changes.
- Update StringMixIn tests to actually work for some of the methods.
- Update copyright notices for the C extensions.