Remove exit, save-as and readonly icons

Decluttering. Object-locked performs the same function as readonly.
Save-as function removed from toolbar as well: the regular save function
is the one that is usually used.
Set correct recording version support
Reorganize export frame size selection inputs
Remove blinking network status icon

The blinking effect was too subtle to be of any use.
TODO: add a statistics dialog that shows the actual byte counts,
latency and average speeds and such.
Standard fill-color icon name
Host dialog initial image size fix

Don't override width/height boxes unless "solid color" is selected when
the dialog is opened.