#59 Force compare

[Ed Burnette]

I modified a file in my local directory but did not "Edit" it
in the P4 sense because I don't have Edit rights on this
project. Therefore P4 doesn't know about my change
and when I do a Compare With > Head Revision it says
there were no changes. I'd like a way to force it to do a
compare (I think the command line client already has an
option for this).