[Greasemonkey] Cross-script configuration data sharing

[Bill Donnelly]

Maybe obvious, but, just in case, a work-around for right now
would be to merge the scripts into one 'super-script.'

For "security's" sake, it might be nice to have a pop-up that
notifies a person that one or more scripts (listed by name?)
with the installing script's namespace currently exist and
do they want to continue? With one of those "Don't ask me this again"
check boxes for 'power users' so they can remove the 'irritation.'
Regardless of whether additional security/access flags and
such are added to the GM_* functions. More information is almost
always better, especially for lay-users.