handle debug flag consistently

use the environment variable for everything.

gets rid of nagging message to make sure DEBUG isn't enabled in production (was
never a concern anyway due to details of mod_wsgi).
add config helper to register handlers for a logger
remove unused store.py logger
added securerop.log for both interfaces to ossec config
added w permissions for securedrop.log in apparmor profile
added logging config to source and document config.py used in production install
cherry-pick umask fixes from develop

This is a slight modification of 1aaf8d58, I had to remove some changes related
to using GPG for OSSEC email alerts (which are not hotfix).
added write perm in apparmor profiles for error.log~ and access.log~
adding a travis yaml file for ci
tweak travis.yml to work on master

master is still using a single config file instead of a module
fix travis.yml due to twill vs. pip

adapted from 1f586ee
Merge pull request #1 from dolanjs/os-apparmor-ossec

OSSEC apparmor and install scripts fixes for logging change
Rip out (unused) mysql dependency

MySQL-Python is breaking Travis builds. Since we don't use it, either in
development or production, I'm removing it.

I also edited setup_ubuntu.sh to remove mysql, but I haven't tested those
changes (it might be broken).
Merge pull request #310 from garrettr/logging-hotfix

Logging hotfix. Fixes #261.