Offline Install Zip Download

code to download app resources as zip usable by commcareodk for offline
install
Merge branch 'master' of https://github.com/dimagi/commcare-hq
Fixes re:PR
remove comments
Merge branch 'master' into offline-install
add toggle_enabled template filter

usage: {% if request|toggle_enabled:MY_TOGGLE %}...{% endif %}
put android offline install UI under a toggle
clean up profile generation variables
make local suite uri behavior completely backwards compatible
minor cleanup of offline-install views

- nicer ZipFile syntax that I also changed elsewhere
- share code with download_index rather than copy-paste
- clean up url patterns syntax
make offline-install zip support unicode
Merge pull request #3489 from dimagi/offline-install

Offline install