Split the Advanced OpenSSH section.

This allows us to link to specific sub-sections for specific operating
systems.

Closes #44.
Revise SSH config file forwarding.

This removes use of the ugly 'parsed-literal' box and [hopefully]
clarifies the instructions a bit.

Closes #46.
Merge branch 'master' into sean/split-advanced-openssh

Conflicts:
	manual/remote-access/gnu-linux/ssh.rst
Parse EOS /etc/hosts file to get EOS hostnames.

This commit touched a lot of parts of the project, and some tooling
improvements were also made.

Closes #15.
Honor auto-update for downloading hosts file.
Add labels back; they are used for BetterPlanner.

This reverts commit d2ff75a826aa3dd0e6f0d2d0964bf4b3c76d159f.
Merge branch 'master' into sean/split-advanced-openssh
Merge branch 'master' into sean/fix-parsed-literal

Conflicts:
	manual/remote-access/gnu-linux/ssh.rst
	manual/remote-access/mac-os-x/ssh.rst
Merge pull request #53 from seanfisk/sean/fix-parsed-literal

Revise SSH config file forwarding.
Merge pull request #49 from seanfisk/sean/split-advanced-openssh

Split the Advanced OpenSSH section.
Merge pull request #57 from seanfisk/parse-hosts-file

Parse EOS /etc/hosts file to get EOS hostnames.
Merge branch 'master' into april/misc-section
Cleaned up the Kill the X Server section.