(#22) Exchanged attribut selectors with css classes.

Conflicts:
	scss/laxar_uikit/_buttons.scss
	themes/default.theme/css/theme.css
(#22). Adapted changelog.
Merge branch 'feature-0.9.x/22-fix-icons-depends-on-position-of-class-ax-icon-or-fa-in-attribute' into release-0.9.x