More CommTrack UI-related stuff

This adds a Reminders tab that is only visible on commtrack-enabled
domains, and hides other irrelevant tabs on commtrack domains.

It also integrates all the existing settings and user pages into the
dynamically generated sidebar framework, including their usage of
"indicators" -- subpages displayed under the sidebar item only when that
subpage is currently active in order to show the user what page they are
on.

For the way I did this to work, it requires a slightly more structured
relationship between urls and views.  No two navigation items on the sidebar
should have the relationship such that one's URL is the beginning of the
other.  So I changed a couple URLs to adhere to that. (This is also true
for the relationship between tabs, subtabs, and pages, and I changed a
couple urls related to that in previous commits.)

Todo: integrate title block into this framework?
Merge branch 'master' into ui-config
move commtrack reports to top of report list
Merge branch 'master' into ui-config
remove commented out code
add more robust handling of active tab for subtabs
add back accidentlly removed commtrack project settings links
Merge branch 'master' into ui-config
merge master
rename SettingsTab back to ProjectSettingsTab
minor cleanup
Add login_and_domain_required to new settings views

so request.domain/project gets set and they don't cause tabs that check
those attributes to be hidden because of AttributeErrors
reminders_content -> main_column
use page-title/subsection-title blocks on reminders pages
Merge pull request #639 from dimagi/ui-config

more commtrack ui-related stuff