Hash::Merge::Simple will recursively merge two or more hashes and return
the result as a new hash reference. The merge function will descend and
merge hashes that exist under the same node in both the left and right
hash, but doesn't attempt to combine arrays, objects, scalars, or anything
else. The rightmost hash also takes precedence, replacing whatever was in
the left hash if a conflict occurs.

This code was pretty much taken straight from the Catalyst::Utils manpage,
and modified to handle more than 2 hashes at the same time.