Merge pull request #364 from mirage/master

constraint core.109.07.00 as Linux-only
Merge pull request #365 from mirage/master

atdgen version updates
added release 1.3.0 of utop
Merge pull request #366 from diml/master

added utop 1.3.0
camlimages: lablgtk is an optional dependency

since lablgtk is a pain to install, this simplifies using camlimages for common formats that dont need lablgtk