Address bar keys (bug #1012)

Hi again,

I was just wondering, could we add an option to control the address
bar key bindings?  I know they're set to behave like a Unix command
line, which can be convenient, but it also interferes with some custom
key bindings (as one of my users mentioned in bug #1012).

I've also noticed that the address bar bindings confuse a lot of
people, since they're not used to the Unix behavior.  Conventionally,
Ctrl-A is "select all," and other input boxes in Dillo follow that, so
they aren't expecting it to go to the beginning of the line instead.

I'll be happy to write the patch, I just wanted to see if anyone would
be willing to commit it first. :-)

Cheers,
~Benjamin