port from django - collection bug

[oberhamsi]

this bug collects all commits we should/could port from django

as of 14/3:

improve {% include %} .. support recursion among other things
django/django@e2f0622

widthratio: Inf/Nan
django/django@07ae47f

widthratio: allow "as" param
django/django@ff41056

Fix #20745: Don't silence TypeError raised inside templates.
django/django@28a5713

simplify filterExpression.args_check
django/django@7c6f2dd

Fixed #7557 -- Added type checking to Variable initialization.
django/django@7fec5a2

cache missing templates
django/django@b785a80