crosh: move rarely used commands from help to help_advanced

Add a new "help_advanced" command for help about debugging or more
advanced commands. This makes the output of "help" clearer and
removes the need for a paginated output.

BUG=chromium-os:12768,chromium-os:19672
TEST=Run "crosh --dev --usb", check that the output of "help" and
"help_advanced" fit in a page and that every command is present.

Change-Id: I31bac1cca20b3e8e6d4db911e426f854e050e1ec
Reviewed-on: http://gerrit.chromium.org/gerrit/6816
Tested-by: Guillaume Brunerie <guillaume.brunerie@gmail.com>
Reviewed-by: Daniel Erat <derat@chromium.org>
1 file changed