Patch to make PartController::editDocument() more robust

[Hamish Rodda]

Victor Röder wrote:
>> Hi,
>> 
>> Some parts call editDocument() with just the filename, so I made
>> editDocument() check in the project's current file list to see if the
>> file is
>> known. See attached patch.
>> 
>> Next we should probably promp the user to locate the real url when this
>> method
>> fails, but I haven't written that yet.
>> 
>> Comments / ok to apply?
> 
> Seems to be okay. If no one commits it, I will hopefully commit it next
> week.

I don't mind committing it if you want.

Also, my next step is to add the ability to call editDocument() with a
function signature as the argument (perhaps add a method editFunction(const
QString& signature); ). Any tips about how to do this in a
language-independent way before I try?

Cheers,

Hamish.