Cache jinja2 bytecode on memcache

[ergoithz]

A custom jinja2.BytecodeCache class (see http://jinja.pocoo.org/docs/dev/api/#bytecode-cache) can be set on (http://jinja.pocoo.org/docs/dev/api/#jinja2.Environment) available at flask.app's jinja_env attribute, providing dynamic jinja2 bytecode cache without filesystem.

[waprin]

Thanks for the suggestion, it does seem like a good feature, but this repo is supposed to be a minimal example, so I would vote against adding too much random stuff. There are more fleshed out skeletons out there like here. If @jonparrott likes the idea I am not against it, but closing for now.

[theacodes]

I'd rather us not do that. It's actually better to do precompiled templates or enable the in-memory cache than to store them in memcache.