Merge pull request #1 from royaldark/master

update to latest version
Added handling of IndexOutOfBounds exception, with and without a message.
Added a type and error message for ref, figured out namespaces when testing via eval
Added NullPointerException, added testing for exceptions
Fixed a couple of minor issues
Separated gui into its own file.
Merge pull request #1 from royaldark/master

Pull
Added draw-polygon, not quite done however and started some additional core functions
Merge branch 'master' of https://github.com/Paul-Schliep/clojure-intro-class

Conflicts:
	src/corefns/core.clj
	src/intro/core.clj
Added draw-polygon to intro class and added additional
(NullPointerException) to the error message associated with that.
Updated dependencies (Clojure 1.5, Seesaw 1.4.3)
Added tab with original stacktrace in error window
"Non-existing" is a nonexistent word :P. Fixed spelling.
Merge pull request #2 from royaldark/master

update to latest version
Committing changes before a merge. The project currently has an error.
Not sure what the conflicts were, but they seem to be happily merged now

Merge branch 'master' of git://github.com/royaldark/clojure-intro-class

Conflicts:
	src/errors/core.clj
Added draw-spiral to clojure intro class
Error windows pop up on top now. Somehow the first error message has a different formatting, need to fix this.
Added back Joe's second tab for stack trace
Added error handling for nth, although the preconditions don't seem to fire.