fix canvas sizing issues
refactor selection layer to go with new architecture
working selection
small fix
fix method we access nodes so we can account for true pixel position regardless of scale and translation
make selectionLayer not a plugin
make selection layer a plugin
small fix - how did this work earlier??
unselect nodes on mousedown
fix, for real
Merge pull request #69 from jdhenke/selection

Selection
add plugin box
ignore previous code
add abstract plugin view
remove plugin abstraction, add wrapper instead
positioning
collapse / expand plugins
stylish stuff
change color of threshold line for prettiness. feel free to override
fix up css