Add Fedora Corp to README

Fedora users now can use Corp (it is like PPA, but for Fedora) and install Final Term without compiling. 

Fedora Magazine link to this Corp in post about [Final Term](http://fedoramagazine.org/final-term-a-new-terminal-emulator-in-development/). I take Corp terminal commands from [Moka instructions](http://mokaproject.com/moka-icon-theme/download/fedora/).