[PATCH] Add move constructor and move assignment operator for FileName class

[Yuriy Skalko]

>> Also I noticed that these files are accessed on every keypress (even
>> on navigating document with arrows):
>>
>> lib/images/undo.svgz
>> lib/images/textstyle-apply.svgz
>> lib/images/paste.svgz
>>
>> Is it *really* necessary?
> 
> 
> It would be because of getStatus, I suspect, though I'm not sure why the
> files would be accessed. Maybe because the toolbar items are being
> enabled/disabled? But surely that only need happen if there's been a change.
> 
> Riki


> Only these files?
> 
> JMarc

Yes, only these 3.

Seems like this is caused by `getIcon` calls in 
DynamicMenuButton::updateTriggered (called on every toolbar update, that 
happens on every key press). And `getIcon` doesn't just return icon from 
some cache, but directly checks the file on disk. I'm not sure how to 
fix it the right way.

Now almost full update of GUI state update (dialogs, toolbars, 
statusbar) is done in GuiView::restartCaret that is called in several 
places in GuiApplication::processKeySym. It will be great to implement 
more fine-grained control of the GUI update.


Yuriy