[db] improves comments for Block in topology
[db] makes vertex block read only, adds vertex doccumentation
[db] adds dragging blocks to the right
[db] can now drag blocks to the left, except to the far left
[db] snaps now using new spacer strategy
[db] refactors getLeftRightSpacers from MyContainer, untested change to
self regulate spacers list
[db] adds initializing drag event to snaps
[db] makes drag information into a dictionary - snaps now cause blocks
to drag too
[db] adds connection link to snaps
[db] snaps print altitude connections
[db] snaps can now be dragged to the right
[db] cleaned up getLeftSpacer and getRightSpacer for snaps
[db] cleans up the snap dropping code a bit, now dragging to the left
too. Buggy
[db] more code cleanup - should not be any change in functionality
[db] seems to fix snaps not always dragging. fixes #13
[db] fixes error in snaps posBand negBand when emitters or collectors
list is empty
dragging vertex1 to the right one spot caused connection to disappear. fixes #11