busybox 1.2.1, 1.2.2: Enabled nohup applet.

busybox 1.2.1, 1.2.2: Enabled nohup applet.
* Being able to login via telnet/ssh/on-device shell and run application such
that it continues to run after logout, should be pretty useful feature for
embedded system.
* With common config (also used by angstrom), doesn't lead to increase of
exe size (due to alignment padding), and the applet code itself is small
(40 lines).
* Approved by Koen Kooi.