Added Refresh Token support Facebook
Added Refresh Token support Facebook

Facebook uses refresh tokens (as you can tell form its use of the `expires` data, and now that offline_access is being removed its even more important to support this.
MaDKaTZe/PHPoAuthLib,Surfoo/PHPoAuthLib,ChaosPower/PHPoAuthLib,lussn/PHPoAuthLib,leansoft/PHPoAuthLib,elliotchance/PHPoAuthLib,canfiax/PHPoAuthLib,PeeHaa/PHPoAuthLib,sebastian301082/PHPoAuthLib,flavioheleno/PHPoAuthLib,geodeveloper/PHPoAuthLib,JLueke/PHPoAuthLib,RewardGateway/PHPoAuthLib,huitiemesens/PHPoAuthLib,gasparfm/PHPoAuthLib,develme/PHPoAuthLib,hanneskaeufler/PHPoAuthLib,Fruitware/PHPoAuthLib,i-am-ains-ly/PHPoAuthLib,defragmentator/PHPoAuthLib,sellerlabs/oauth-php