Update version to 1.0.4.1
.gitignore
plugin.xml: Fix broken command definitions so that they actually appear in "Genral / Keys" in preferences window
Change font size increment to 0.1 since in Linux the rendering engine might render font sizes 7.4 and 7.5 slightly different (and also different from 7 or 8), allowing to select an optimal "subpixel" font size easily.
Add basic plugin branding for better appearance in About dialog
Refactor font adjustments to use helper class