add fullscreen button

[banglashi]

No description provided.

[mntmn]

Can you explain the use case vs using the browser's built-in button / key (F11)? Is this for embedded spaces?

[mntmn]

See #104 (comment)

[banglashi]

Hi @mntmn,
I like the idea of adding it to a "View" dropdown. The use case is the same as the browser's built-in button / key (F11) but I think a lot of "normal" users are not aware of this.

[plomlompom]

I assume a fullscreen option mostly benefits users with smaller screen estate, so they can make maximum use of the little they have. But in such a context, the low placement of the fullscreen button defeats its purpose (as I just tested on my common screen resolution of 768 lines): For non-fullscreen views, it stretches the button sequence beyond the lower margin of the screen, with the very button to get into fullscreen mode easily sliding out of visibility. Not sure what the elegant solution to that would be though.