Added function to stop browsing.

[nleclerc]

Nothing to add :-)

[jarnoh]

Actually, I think calling browse() without parameters does stop browsing already?

[nleclerc]

Now that you mention it, it probably does but i don't think it makes sense semantically speaking.

Don't you think it's better if browse without parms gives an error and there's a separate stop function ?

Note that i didn't add an error when calling browse without parms, i'm just saying :-)