GC Issue 99: Incorrect error with if-let

Removed obsolete patch from Feb 23 2012. Preference should be given to patch clj-103-improved-if-let-error-message-patch.txt dated Apr 20 2012 instead.

I like the improved wording. I struggled with that myself. Thanks Brenton!

The provided patch from John and updated by Andy

clj-103-incorrect-if-let-error-patch2.txt

applies cleanly and doesn't cause any problems. I don't like the wording of the error message: "requires 1 or 2 forms to be passed" so I added another patch

clj-103-improved-if-let-error-message-patch.txt

which is the same change but with the wording "requires 1 or 2 forms after binding vector" which I think is a little more clear.

With this change, a user would now get the following error messages:

clj-103-incorrect-if-let-error-patch2.txt is same as John's except updated to apply cleanly to latest master as of Feb 23, 2012. No compiler errors or warnings, no test failures. No new tests for this one – I could write one, but the only way to do so is to check the contents of the error message in the exception thrown, which seems a bit too specific. The author John Szakmeister is on the contributor list.

First iteration of the patch.