Yet another trace library.

[hjlee]

While searching usable trace libray in clojure,
I found 3 pieces of codes.

- Stuart Sierra's clojure.contrib.trace

- Rich Hickey's posting
http://groups.google.com/group/clojure/browse_thread/thread/fd315d9dfdb8c32c/7479682cdf3a1b97?lnk=gst&q=trace#7479682cdf3a1b97

- Craig McDaniel's trace2.clj
http://groups.google.com/group/clojure/browse_thread/thread/3ea8777880231e18/6fd1b352ac1a6744?lnk=gst&q=trace#6fd1b352ac1a6744

1st can be used to trace any expression. but it's not for general
function tracing.
2nd version works well.
3rd version provide trace-ns, untrace-ns. but no indentation on trace
output.

So I combined indented output part of the 2nd codes to the 3rd codes.
And provided some control vars on output contents.

http://groups.google.com/group/clojure/web/trace_fn.clj

Any comment?