Correct impl. of quad, add test
Make default repl profile for build not run tests
Make GershwinStack/peek act like normal Clojure peek, add peekSafe

The peekSafe method throws an exception if the stack is empty, which is the desired effect when evaluating Gershwin words that are implemented with peek, but this caused confusion with Clojure's own peek.
The each word should not put nil on the stack
Implement every? using quotations
Add coll? predicate
Implement short-circuiting and called and-greedy
Ignore *gershwin-eval* for time being
Add utility to-upper-case and to-lower-case for Java interop on Strings