[ECOS] Main loop user callback mechanism patch attached.

[Grant Edwards]

Attached is a patch that uses the HAL_TABLE mechanism to allow
the user to register a main-loop callback routine via the macro
RedBoot_loop() much the same why you can register an
initialization routine using RedBoot_init().

NB: This patch also changes the main-loop gets() timeout from
    250ms to 10ms.  I was thinking about making that value
    adjustable via cdl, but haven't done it.

-- 
Grant Edwards
grante@visi.com