closes #1935 staff 500 page
styling fix for 500 pg
WIP doing email stacktrace
make sure that the stacktrace gets logged and sent
fixes #1917.  Say it ain't so, Joe.

I'm leaving this commit message obtuse also because it's fun to
figure out what this change fixes a db integrity bug.
missed one spot
Enable CacheStats in common_page_data
Fix static page exception when no ContentGroups

* Recent refactoring introduced a bug that caused an exception when a
  static page with no ContentGroup entries (such as Overview) was
  rendered.  This fixes it.
Merge pull request #1985 from Stanford-Online/jrbl-enable-cachestats-in-common-page-data

Enable CacheStats in common_page_data
scalyr-agent: initial support (#1987)
scalyr-agent: fix apache log location (#1987)
add key for sending logs to scalyr (#1987)
scalyr-agent: fetch instead of distribute installer (#1987)
scalyr: factor into separate role (#1987)

It's just a bit flaky, so to start let's try this on some specific
machines to make sure it doesn't cause any trouble.  May move it into
the mainline recipes at some point later.
scalyr: agent dir pernms, runlevels, start quietly (#1987)
scalyr-agent: link directly to script for startup (#1987)

This is bad practice, but the only way to have their init script
work on startup due to some weird user changing stuff they're doing.
scalyr: add comment for workarounds (#1987)
Merge pull request #1963 from Stanford-Online/jbau-db-integrity-fix

Jbau db integrity fix
make it clearer that the attempts label is a link to scores

Not black anymore if it's a link - link-colored like other links on the
site, and new parenthetical "(see scores)"
Merge pull request #1992 from Stanford-Online/sef-1987-scalyr

deploy scalyr-agent as an optional role (#1987)