Fix issues with note sizing caused by the switch to `box-sizing: border-box`
in 19aea560. Note boxes have a 1px black border, which is counted as
part of the note box width when using border-box. This threw off sizing
and position calculations.
Also go back to 1px borders instead of 2px borders for unsaved and
selected notes. This also messed up note sizing.
de44f6c8e4