Update CMakeLists.txt

Remove invalid reference from build system
Reintroduced unwrap continuation
Adjust .then implicit unwrapping
Adjust unwrap regression test case
Reintroduce fixed "Instead of sending a managed target id for the action triggered by a future we now keep that id alive locally. That will reduce the amount of necessary id splitting."

This reverts commit 990d2b8c96316cb27ad86ee98eb14c8c7868e974.
Adjust unwrap regression test case
Removes unwrap member function (the unwrapping constructor remains).
changed foreach_scaling output to csv
Merge branch 'master' of https://github.com/STEllAR-GROUP/hpx
Adding a second pipeline example
Merge pull request #1184 from STEllAR-GROUP/unwrap

Tweaking future unwrapping
Fix for unwrap continuations
commented out unused variable
Adding assert verifying that futures are ready when serialized
Remove example pipeline2
Merge branch 'master' into fixing_1189

Conflicts:
	examples/quickstart/CMakeLists.txt
	hpx/lcos/async.hpp
	hpx/lcos/preprocessed/async_10.hpp
	hpx/lcos/preprocessed/async_15.hpp
	hpx/lcos/preprocessed/async_20.hpp
	hpx/lcos/preprocessed/async_5.hpp
Fixing merge conflicts