make all demos/ for each release available through some URL

[bill]

As per #7344, [14644], [14648], etc. demos are being moved to demos/ rather than dijit/demos, and *some* of them will be exposed through dojotoolkit.org/demos but unclear which ones/when.

Currently all the dijit demos for any release can be accessed through a URL to download.dtk.org, for example ​http://download.dojotoolkit.org/release-1.1.0/dojo-release-1.1.0/dijit/demos/mail.html

They are also on archive.dojotoolkit.org but that only contains recent snapshots; it doesn't go back to previous releases.

So, need to make sure that all the demos are accessible through a URL somewhere, maybe on archive.dojotoolkit.org, but preferably:

• putting them in the download.dtk.org main folder (see above link) and -src zip file
• don't include them in the -mini zip file
• make the mini -zip file the official download

(The last step is to quell fears from Alex that our demos make dojo look bad, and also to avoid possible copyright issues with redestributing icons / other stuff w/license issues)

[dante]

(In [14794]) refs #7360 - all the demos have been moved, and the remaining items of this ticket will be addressed at 1.2 release.