cljs alt! tests pass
added try/catch/finally to cljs
remove some debug calls
Fix race in multiplexing, dispatch handlers

Because of the recur points in the impl, alt and take handlers can
occur in the dispatch pool (after a source dries up), in which case
returning the gotten val will just disappear. Make sure to run handlers.
refactor source to make Maven happy
fix file suffix for cljs files
Fix race in callback test
Merge branch 'master' into forkjoin