Add About document.

Closes #20.
Comment the History section (for now).
Merge pull request #61 from seanfisk/sean/about-meos

Add About document.
Revamp Editors section.

Closes #28.
Add uptime to misc section.
Fix multiply-defined labels issue in LaTeX.
Remove unnecessary backticks.
Fix color of developer mode config value.
Add a todo to the Waf-Sphinx tool.
Correct Waf version in Sphinx tool.
Warn that 'makeglossaries' may be missing.
Change grammar in uptime section.
Merge pull request #65 from seanfisk/sean/editors

Revamp Editors section.
Merge pull request #66 from seanfisk/april/misc-uptime

Add uptime to misc section.
Add openers for various formats to Waf.
Merge pull request #69 from seanfisk/sean/openers

Add openers for various formats to Waf.
Merge branch 'master' into mick/misc/xdg-open

Conflicts:
	manual/misc.rst