Upgrade bundled cherrypy

[matthewrmshin]

We need to upgrade cherrypy (from modified 3.2 to 10) and jinja2 (from 2.8 to 2.9).

(cherrypy is going to be more challenging as it has been modified in several changesets.)

[matthewrmshin]

Version number of cherrypy is going up like crazy in the last year (>30 releases since June 2016 and >10 releases since Boxing Day 2016!) It is now impossible to determine what is the stable release - with 2 major releases within 2 days - only a few days ago. The project is also being split into 3 parts, so it may become a pain to bundle in the future. If situation does not improve, we may need to consider moving to another web framework, e.g. flask or perhaps tornado.

[hjoliver]

The Jinja2 upgrade is somewhat urgent, in that users (in a suite portability context) have run into a bug in 2.8 that I have confirmed is fixed in 2.9. The bug should probably be documented in the Suite Design Guide where use of {% import ... %} is mentioned. Details, for the record:

Jinja2 variables defined in the top level template (i.e. suite.rc) are available to sub-templates via {% include ... %} but not via {% import ... %} unless with context is added to the import statement.

E.g. if sub.rc is:

{% set RESULT = STUFF | default("ERROR") %}

then the following will print # ERROR under jinja2 v 2.8 and (correctly) # stuff at v 2.9:

{% set STUFF = "stuff" %}
{% from 'sub.rc' import RESULT with context %}
# {{RESULT}}

As a workaround I've found the following does work at 2.8:

{% set STUFF = "stuff" %}
{% import 'sub.rc' as SUB with context %}
# {{SUB.RESULT}}

[matthewrmshin]

Superseded by #2563.