Use system font

Just for fun....   
### macOS Chrome (San Francisco):   
![Screen_Shot_2016-11-17_at_4.01.29_PM](/uploads/bfbab440ea0136314a6a7cffcd44f3ff/Screen_Shot_2016-11-17_at_4.01.29_PM.png)
### macOS Safari (San Francisco):   
![Screen_Shot_2016-11-18_at_8.28.22_AM](/uploads/3adc05d7adf84ca726cbaaf36cb0567d/Screen_Shot_2016-11-18_at_8.28.22_AM.png)
#### Ubuntu Firefox (Ubuntu): 
![Screen_Shot_2016-11-18_at_8.31.08_AM](/uploads/0f0d581d2d79d5db3dba9b2200499dc7/Screen_Shot_2016-11-18_at_8.31.08_AM.png)
#### Windows 7 IE 11 (Segoe UI): 
![Screen_Shot_2016-11-18_at_8.35.05_AM](/uploads/88efc2c554252de03fb84cc3c3e2856e/Screen_Shot_2016-11-18_at_8.35.05_AM.png)

See merge request !7545