Add zip operator including tests
Clang compilation fixes
Disable clang optimization that spoils value extracted from list.
[[clang::optnone]] attribute doesn't work on OSX

Check whether it is required there at all.
optnone is required for OSX Clang

Try to pass it in old fashion.
Clean zip sources
Disable clang optimization on extract_list_front() for OSX
Merge pull request #50 from ValeriyKopylov/zip

Zip