Print compiler and linker version with the version command

After years of unsuccessful research I've finally shamelessly stolen other
peoples intellectual properties to present the all-new and world-changing
updated version command:
-
U-Boot>> version

U-Boot 2010.12-00014-g7435056-dirty (Jan 18 2011 - 23:19:38)
MyBoard
gcc (GCC) 0.42 (Distro foobar)
GNU ld (GNU Binutils) 0.314159265
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May the toolchain bugs rest in peace.

Signed-off-by: Alexander Holler <holler@ahsoftware.de>