Add hull image preview to ship loader
Added glow image sets loading instead of glows

The editor will try to automatically create appropriate <roomLayout> for
the room/station combination, and use the glow image set specified by
the user.
Continuation of commit 39913853343eb70c7d19f02a92a5cc8c5c8d143d

(forgot to include two files in the previous commit)
Fix door link verification, glow saving, comments
Added info about deletion state to objects
Miscellaneous UI changes and tweaks