[resolver] issue #5 : resolver interface + unit tests from RBPromise
[resolver] issue #5 : migrated code from RBPromise about resolve algorithm
[promise] issue #5 : Use a RBResolver object
[promise] refactored tests to take into account RBResolver object
[travis] travis config
[travis] ensure cocoapods is installed (Travis issue)
[travis] use shared schemes
[travis] set sdks
[travis] install xctool last version + set cocoapods version to use
[travis] install latest xctool version
[project] updated pbx
Merge pull request #6 from KptainO/resolver

Resolver
[project] issue #4: osx support
[pod] issue #4: add osx as supported platform
[travis] try to configure Travis to test on OSX
[project] updated CHANGELOG
[project] fixed pod dependencies and Travis CI
[project] set pod version to 0.27.1 for travis (waiting for https://github.com/CocoaPods/CocoaPods/issues/1549 to be fixed) + some other minor issues
Merge pull request #8 from KptainO/osx

Osx
Merge branch 'development' into action-syntax

Conflicts:
	Rebelle/RBPromise.m
	RebelleTests/RBPromiseTests.m