adding copy method with url change

[horans]

allow user directly switch to certain copy method from url parameters.
the new setCopy() works just like setLibrary().

[thomaspark]

@horans, this is fantastic. Thanks for the contribution!

[thomaspark]

Spotted a small bug: when you delete the copy argument in the URL, the "markup" button is highlighted but what's actually copied is whatever was last selected.

[horans]

i guess its something to do with line 28:
setState("library", qs.library);
i added the line underneath without thinking:
setState("copy", qs.copy);

then, the "state[copy]" will turn "undefined" if the query string is not having "copy=". (same as the "state[library]")

how about change these two lines into:
setState("library", qs.library || "all");
and
setState("copy", qs.copy || "markup");
to set the default value.

[thomaspark]

That should do the trick, and makes lines 40 and 76 redundant.