[PodSourceInstaller] Fix clean paths bug
Make Integration tests more robust
Merge branch 'integration_take_2' into 0.17

* integration_take_2:
  Make Integration tests more robust

Conflicts:
	Gemfile.lock
	spec/integration/install_add_pod/after/Pods/Pods.xcodeproj/project.pbxproj
	spec/integration/install_add_pod/after/execution_output.txt
[Specs Integration] Update install_add_pod
[Spec Integration] Update install_new for 0.17
[Spec Integration] Update install_external_sources for 0.17