When dimensions don't match, print out the variable name involved as well.
fixed dump sign issue as suggested by ksvanhorn in issue #197
removed tabs; indented files using emacs
updated boundary test for test/agrad/rev/acos
updated boundary test for test/agrad/rev/acosh
changing behavior of functions to pass through to the underlying library calls where reasonable. updated tests to show behavior.
Merge pull request #2 from stan-dev/jadams41-agrad/rev-tests

Updating code and tests.