Add Google Authenticator instructions for Android
Include changes suggested by @ageis
Merge pull request #679 from ageis/develop

Add Google Authenticator instructions for Android
Merge branch 'develop' of https://github.com/freedomofpress/securedrop into develop
Merge pull request #681 from runasand/develop

Include changes suggested by @ageis
Updated user manual for 0.3 (todo: screenshots)
Updated with changes from @garrettr
The JavaScript warning really is a popup, not a separate page
Journalists need username, password, 2fa to log in
Nitpick on javascript warning
Merge pull request #687 from runasand/develop

Updated user manual for 0.3 (todo: screenshots)
Split and merge full_install.md into separate, related docs

Also updates instructions, formatting, and cleans up whitespace.
Update grsec kernel build docs to latest built kernel

* Updates the docs for Ubuntu Trusty (14.04.1) because we switched to it for SecureDrop 0.3
* Updates versions of grsecurity patch and linux kernel to the versions used in the most recent successful build of the grsecurity kernel
* Fixes some formatting and trailing whitespace issues
Tip for speeding up dd on Mac OS X
Harden setuid binary for Tails torrc helper
Merge remote-tracking branch 'upstream/develop' into upgrade-and-apply-grsec-first
updated develop.md directions with notes about performance impact of running a grsecurity kernel.