perl-File-pushd (change directory temporarily for a limited scope)

File::pushd does a temporary chdir that is easily and automatically
reverted, similar to pushd in some Unix command shells. It works by
creating an object that caches the original working directory. When
the object is destroyed, the destructor calls chdir to revert to the
original working directory. By storing the object in a lexical
variable with a limited scope, this happens automatically at the end
of the scope.
