Bug#612783: Support initial install from live media plus more from elsewhere

[Ben Armstrong <synrg@sanctuary.nslug.ns.ca>]

Package: live-installer
Severity: wishlist

To address the use case where small media might not be able to contain all
desired packages for a live install, please support installing the contents
of the live media first, followed by a (most likely preseeded) list of
additional materials from another source (most commonly the network, but
any source will do).

Daniel hinted on irc that "multi-fs" support in 3.x could help with this.

Thanks,
Ben