Ddoc for map() should be associated with the function itself.
Do the same for amap and reduce, for consistency's sake.
Remove unused test in std.process

This seems like a remnant from when the first version of std.process was
being developed.  It does not appear to be in use today, so there is no
reason to keep it around.
Merge pull request #2414 from kyllingstad/remove-std-process-maintest

Remove unused test in std.process
Merge pull request #2408 from quickfur/parallelism_ddoc

[dox] Ddoc for std.parallelism.map() should be associated with the function itself.
WIP on refactoring std.process

This is a work in progress, and is not meant to be merged into Phobos
master yet.  The following things have been done so far:

  * Moved spawnProcessImpl() for POSIX and Windows into
    std.internal.process.spawnprocess_posix and
    std.internal.process.spawnprocess_windows, respectively.
  * Moved environ into std.internal.process.environ.
  * Removed most module-level imports in std.process, and added
    function/class-level imports as necessary.
  * Minor cleanup here and there
  * Commented out the old std.process functions *temporarily*,
    to avoid any unintended dependencies on them or their imports.

More changes will follow; I'm only pushing this to be able to use the
auto-tester.
Another way to temporarily disable old functions

The old std.process functions are required by the DMD test suite.
Hopefully, they will now only be disabled while compiling the Phobos
unittests.