Costumes are cut off at the bottom and right on the stage

[fsih]

Expected Behavior

Whole costume should show

Actual Behavior

A couple pixels get cut off on the bottom and right

Steps to Reproduce

Draw a costume, and look carefully at the bottom and right edges

Operating System and Browser

all

[fsih]

Perhaps this bug is the cause of the one remaining issue on #434 (which is now fixed for all line widths except 1px wide)