* Make fallthrough explicit in tok_parse.c

In response to #325

* Update tok_parse.c

* +after param to Template.add

also updates docstring

* Template.add param after test

* Increase MAX_DEPTH to 100

* Update nested_templates_and_style_tags to cover new limit

This regression seems more severe than the bug the commit was
attempting to fix (incorrect parsing of nested wikilinks in normal
links), so that bug is reintroduced until localization-aware parsing
that allows us to detect file links is added.

This commit partially reverts fac60dee48.

Signed-off-by: odidev <odidev@puresoftware.com>