Add core.time.MonoTime.
Replace uses of TickDuration with MonoTime.
fix fenv for Windows
also compile fenv into the lib
Fix 11761: aa.byKey and aa.byValue are not forward ranges.

The problem is that Phobos' `isForwardRange` template requires that
`.save` must be `@property`, otherwise it does not acknowledge the range
as a forward range; however, aa.byKey and aa.byValue's `.save` weren't
marked as such. This PR fixes this problem and introduces a unittest to
ensure the forward range criteria are satisfied.
DRY up the unittest.
Merge pull request #925 from quickfur/issue11761

Fix 11761: aa.byKey and aa.byValue are not forward ranges.
Merge pull request #899 from Trass3r/fixfenv

fix fenv for Windows
MANIFEST is missing bss_section.c
Fix parseMangledName
Merge pull request #926 from WalterBright/manifest

MANIFEST is missing bss_section.c
use CRuntime_DigitalMars/CRuntime_Microsoft instead of Win32/Win64 where appropriate
Merge pull request #927 from sinkuu/fix_demangle

Fix parseMangledName
Merge pull request #928 from rainers/coff32

COFF support for Win32
Merge pull request #847 from jmdavis/monotime

Add MonoTime as a replacement for TickDuration