GCalctool string freeze request

[Robert Ancell <robert ancell gmail com>]

Hi,

I'd like to update the tooltips on the base buttons to include the
shortcut keys, the string changes will be:
"Base 2" -> "Base 2 (Ctrl+B)"
"Base 8" -> "Base 2 (Ctrl+O)"
"Base 16" -> "Base 2 (Ctrl+H)"

These shortcut keys are included in the documentation.  This change is
to help users discover the shortcuts for these operations (which users
want to be able to do quickly for converting between bases).