BasicCommands, imported, needs review

[Matthew East]

I've imported the BasicCommands wiki article to our repo. The idea is to
include it in the system documentation under the "Advanced Topics"
topic. There is a placeholder link there already for it, in fact.

Can some people review it? There will probably be quite a few issues as
a result of the wiki -> moin conversion, so please take a look! Also any
substantive comments are welcome, although these should be fixed on the
wiki as well :)

Matt
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http://www.mdke.org
gnupg pub 1024D/0E6B06FF