Adding McKayla, GoT, Morpheus, and Bear Grylls

hubot memegen <text> NOT IMPRESSED - Generates McKayla Maroney
hubot memegen PREPARE YOURSELF <text> - Generates GoT
hubot memegen WHAT IF I TOLD YOU <text> - Generates Morpheus
hubot memegen <text> BETTER DRINK MY OWN PISS - Generates Bear Grylls