cleaning up compile-time warnings

[Jon Trowbridge <trow novell com>]

It seems like mcs has been getting a lot more strict, and a lot more
warnings are being spewed to the console when Beagle is being compiled.

A simple and useful project for someone would be to systematically check
warnings and make any necessary corrections (often just a minor tweak)
to make it go away.  All of the (presumably) spurious warnings make it
harder to spot real problems.

-J