Implement RImageEntity and related classes.

DONE

Image in block

Image insertion tool:

• change size in options tool bar: keep ratio

Image file look up:

• absolute path
• relative path (?)
• same path as drawing file

Image display:

• draft: border
• normal: image
• preview: border (or image for small file)

Move, rotate, ...

POSTPONED

Selection with click inside image

Move reference points to scale