Fix numeral scaling for icon_layers without scale specification

[kirazy]

1. Adjusted precendence for icons vs icon, moved return icons above return icon in function get_icons()
2. Baked 0.5 scaling factor into icon_size_scale calculation for instances where scale is specified, and where it is not, icon_size_scale is 0.5.
3. Added brackets around 10.24 / 32 on line 172 to make parser happy
4. Cleaned up trailing whitespace