#1 Mathematical operations can be inaccurate

[Mark Schnitzius]

All math operations are currently performed using the
standard operators on Java "double" types.

These operations should instead be performed in a safe
manor, so that the correct result is always guaranteed
to be within the outer bounds of the interval.

Unsafely applying just the Java standard operators on
the "double" endpoints is fundamentally at odds with
what interval arithmetic is supposed to be about, and
will be addressed as soon as possible. For the time
being, though, it provides a simpler implementation
that will suffice until various design issues are
worked out.