fix #31411: swap icons for vertical and horizontal raster

see http://musescore.org/en/node/31376#comment-137401
less coarse spinbox resolution for beam slope

see http://musescore.org/en/node/32686#comment-137041
Merge pull request #1299 from Jojo-Schmitz/ui

fix for #31411 and finer spinbox resolution for beams