[db] edits v5.xml to be more accurate to the original drawing
[db] band rank drawing order now enforced. fixes #24
[db] fills in qt horizontal bands. fixes #31
[db] adds comments to SpacerContainer.
fixes #29
[db] tries to make the cornering on bands a little nicer, didn't do much
[db] moves blockitem list and banditem list into their spacer containers
fixes #18
[db] fixes isUsed to recognize when an edge is not fully connected
[db] removes unused commented out code from qtview
[db] adds example test diarc xml file
[db] RSG reports nodes in a dictionary by name
[db] topics no longer report as name,type pairs in rsg.topics
[db] removes lists of visual qt objects to reduce their pointer count.
this keeps them only known by their parent and by the topology
[db] removed unnecessary visual attribute from non-visual object
[db] deleted previously commented out line
[db] saved state
[db] adds some more release code to diarc topology
[db] adds mechanism to release() vertex, edge, and conn objects from topology
solves #35 and fixes #37
[db] implements _release() for BandItem, BlockItem, and SnapItem
[db] removes  remove() that was never implemented in favor of release()
[db] updates ros hooks to RsgUpdater that can in theory remove items