use webbrowser module if no browser found
add chrome to browser list
handle errors on Popen and webbrowser
don't ask contradicting questions

When we ask two questions and take only one answer,
the answer should work for both questions!

The answers to both question could still be different,
but we do want to push users a bit to attach disc IDs
to new releases.
be less explicit on browser option

We now have several ways trying to detect the default browser:
xdg-open, x-www-browser, webbrowser module and a static list.
Explaining all of this in the description makes it quite difficult.

Most people only want to know that they can, but don't have to set this
option in order to get a browser "connected".

The few users that actually do care will find the BROWSERS variable
right at the top of the script.
Merge branch 'webbrowser'

see pull request #77

Conflicts:
	isrcsubmit.py