Add Reddit Share button to Hexo's Landscape theme

I have added a Reddit button to Hexo’s Landscape theme by re-using existing code for Pinterest’s share button (found by searching Landscape’s Github repo for references to Pinterest), with minor modifications specific to Reddit.

Additionally, I had to update font-awesome to its latest git version as version 4.2 does not provide a reddit icon.

The changes I made can be found in this Git commit