[db] save point - bands things are drawing nicely
[db]  makes it a little easier to drag about - also removes a bunch of
print statements
[db] adjustments to qtview sizing policy
[db] re-enables isUsed and isLinked for snaps
[db] various changes
[db] adds spacer in middle of Blocks
[db] adds names to ros_diarc - fixes #46
[db] initial work on the explicit MVA
It renders - but with some issues
Some snaps seem to be drawing over top of each other
items never get removed so once one should be hidden things break
Interactions are all broken due to items never being removed