Wait for asynchronous task to finish with the completion block invoked in unit tests
Merge pull request #2 from bcylin/async-test

Test asynchronous tasks
commit for v0.3
Merge branch 'master' of github.com:pixnet/pixnet-ios-sdk
remove files
remove files in proj.
UserForTest class add to gitignore.
add judgement is the same user.
add isAuthed method in PIXNETSDK class.
credential store bug fix.
check point updated.
logout method added.
remove something useless.
bug fixed.
tag friend method added.
update tagged in element done.
delete tagged face methods added.
test album class methods flow done.