remove debug
fix date filter for timestamp 0
unit test timestamp parsing
refine date filter argument detection; allow java.util.Date
filter not implemented
fix intra doc link
more prominent docs
there's no table
add another link
minor
gr
if the variable can't be fully resolved return last resolved part

e.g. assume `{{session.data.user.name}}` if user is null we should return
null (not the empty string as it was now).
make "INVALID" configurable and default to "" (empty string)

see docs/undefined-variables.md
template origin is now public but only set if DEBUG=true; added unit tests for this

see https://github.com/django/django/commit/8625c7aab3760d16572792fea23a95e572e28ead
{% include %} tag accepts variable

if that variable is an object with `render()` it is assumed
to be a template.

see https://github.com/django/django/commit/5cdacbda034af928f5033c9afc7b50ee0b13f75c
add regression test for c175d09eeb98d1c9e8c
bump version