Protect against a nil NSURLSessionTask and an unreachable upload file path.
fix urlencoding on tokenless requests.
use api module version config
new facebook error code
add urlencoding
add endSession to PRM
 Merge branch '2.0.1.bugfixes' into 'master'

2.0.1.Bugfixes

add 2.0.1 changes so we can tag master
rename description field
Global authentication failure handler, MFConfig cleanup
pass response of get_session_token up the callback chain
ignore
remove xcuserdata
update parallel lifespan
 Merge branch '2.0.2.ios8' into 'master'

2.0.2 Release