[executer] fixed execute selector code not always queued
Cancel RBExecuter (issue #1)
[promise] add cancel/abort methods (issue #1)
[promise] added unit test for result value checking (issue #2)
[promise] refactored big part of the logic into setState: and setResult_: (issue #2)
[executer] moved all logical execution code into internal method. Now execute:withValue: does only ONE job: to proxy
[tests] separated tests on RBPromise and RBExecuter + simplified them
[promise] fixed call to resolve: with the wrong result value inside then block
[promise] fixed issue where removing observer too soon could cause a crash
[project] updated pbx
Merge branch 'master' into development
[promise] override setExecuter_ to add/remove KVO on it
[project] export headers into Rebelle.h
[pod] version 1.1.0