add sass
add .ruby-version file
add mouse position to dimension widget
store reference to frame, vendor jquery, and add helper functions:

- get current css translation value of element
- compute new translation value given desired center
create Node object to store/show dimensions of each resizable div
- Node now correctly computes its center
- each Node has its own center dot
- widget shows node dimensions
- re-centering nodes in container does not yet work correctly
move node dimensions widget and center dot div elements out of nodes

they are created independently and passed into Node object
set element scale without clearing translate transform

create nodes for frame and container elements and use them in function that computes container translation for centering an element