Fixed #1176: HPX_DEFINE_COMPONENT_CONST_ACTION_TPL does not have a 2-argument version. This also adds other similar macros which were missing (HPX_DEFINE_COMPONENT_ACTION_TPL, HPX_DEFINE_COMPONENT_DIRECT_ACTION_TPL, HPX_DEFINE_COMPONENT_CONST_ACTION_TPL, and HPX_DEFINE_COMPONENT_CONST_DIRECT_ACTION_TPL).
Fixing #1177: MPI parcelport defect
Working on docs
Adding more docs to parallel algorithms
Modified sequential copy_n and copy_if to forward to std
Implemented variadic zip_iterator.
Replaced range-based for loop with BOOST_FOREACH to support old compilers
Finished docs for parallel algorithms
First pass over N4071, adjusting our implementation to conform to newest specification
Adding parallel algorithms section to docs
Minor documentation teaks.
Merge branch 'master' into zip_iterator

Conflicts:
	hpx/parallel/detail/zip_iterator.hpp
Resolve merge issues
Merge pull request #1178 from STEllAR-GROUP/zip_iterator

Implemented variadic zip_iterator.
Fixed annoying comparison between signed and unsigned warning
Removed wrong assert
Fixed is_callable to consider dereference operators as targets for mem-ptrs
Some when_each/wait_each fixes. Use them in examples and tests instead of the old wait where possible.
Handling warning generated by newest Windows SDK
Handling warnings issued by newest version of PVS Studio