The patch enhances webbrowser.py.

First, all calls to os.system return result code, and
the inverse of the code (it is ok/fail status) passed
through all higher-level routines up to top-level call
to open(url). This allows to check if a browser was
really started.

Second, the very open() modified so it is now trying to
run all registered browsers in order until a browser
returns 1.

Third, the file can be used as a program: webbrowser.py
url. Optional parameters -n allows to open the url in a
new window.