Ux/improved hover and select

[argyleink]

i'm actually not convinced this is better. needs more work, but want to post it for anyone to peep. love to hear thoughts.

known issues:

• labels and other items supposed to be "attached" to the node, dont track changes anymore. needs observer to notify subscribers
• multiselect only highlights one
• not all tools should/need some of these features, still trying to find a proper mixture of ui feedback

things to try:

• inspector
• guides tool
• any other tool (get the new hover feedback like devtools)

[argyleink]

feeling much better in the newer iteration

[argyleink]

this is ready for QA, I think it's ready to merge, feels very nice, and is clean in the DOM