Improved content and layout of OFL button and tooltips


also getting rid of duplicated lines and error: 
sys1: PangoWarning: pango_layout_set_text: assertion `lenght == 0 || test !=
I guess the full text was "Add SIL OFL", represented by the "Add SIL" string followed by the OFL logo &ndash; this was significantly more concise imo. 
Most importantly the word "Automatically" does not seem to serve any purpose here: if there is a button to add it it seems obvious that it's to be done for you.