Uncaught exceptions causes REPL input to hang

[weavejester]

Running a line of code like:

(throw "foo")

Will cause the REPL input to hang.

[cemerick]

Right, that's caused by this (catching js/Error).

Austin will be getting its own client-side implementation in #50, which will fix this. In the meantime, a fix (or ticket, anyway) for this in the stock ClojureScript browser REPL would probably be appreciated.