Fix level editor surface pixelation when window resized on subtab
Fix level editor surface pixelation when window resized on subtab

Noticed that the canvas was getting width of 100 set when window
  resized while the canvas was not visible, so we check for greater
  than 100 width as a simple fix.

codecombat/codecombat,javatlacati/codecombat,javatlacati/codecombat,javatlacati/codecombat,javatlacati/codecombat,javatlacati/codecombat,codecombat/codecombat,codecombat/codecombat,codecombat/codecombat,codecombat/codecombat