Add the option to choose the font family of the Google fonts

[ks888]

Suggestion from @kaustubhmenon https://github.com/ks888/LambStatus/issues/14#issuecomment-365342914

My question: Does it mean the option to choose the font family of the Google fonts? That sounds interesting.

Reply: Yes, a dropdown with a list of google fonts to choose from in the settings page. Where the user can choose fonts for Page Headers and Paragraphs(General Text).