Add version number, frmROM improvements

* Version number is now displayed on the main form and ROM form
* The "No" icon is now shown when dragging invalid files over the ROM
form
* The invalid ROM warning remains until the user mouses out of the form
Set the MDI form minimum size

The minimum form size is now set by mdiMain, and not the child form
frmLevel. This means that the minimum size is now app-wide, but frmLevel
will need to more gracefully handle the minimum size
bluControlBox: Automatically hide control if sizer, and parent form maximises

In-built glue!
Custom min/max/close buttons hide/show automatically based on borderless UI turning on/off

bluControlBox automatically hides/shows based on bluWindow status
Changed `LenB` use to `Len`, it works safer for some reason