vector_dotproduct example added
Merge branch 'master' of https://github.com/STEllAR-GROUP/hpx
Adding closed tickets to docs
Moving zip_iterator to hpx::util::zip_iterator
Spawning thread in invoke_when_ready with high priority
Adding more forwarding headers
Switching vector-dot-product example to use double for the intermediate results
Revert "Switching vector-dot-product example to use double for the intermediate results"

This reverts commit d987d50f3bce5728fafd195a1f63408a15e27ce5.
Fixed zip_iterator category