Make std.datetime.Date @safe.
Make std.datetime.TimeOfDay @safe.
Make std.datetime.DateTime @safe.
Fix property enforcements in `std.range` mixins.
Make time zones @safe.
Make std.datetime.SysTime @safe.
Merge pull request #2244 from jmdavis/safe

Make most of std.datetime @safe
Merge pull request #2245 from denis-sh/fix-property-enforcements-in-`std.range`-mixins

Fix property enforcements in `std.range` mixins.
Fix BitArray.opCmp
Fix codestyle code review comment
Fix code review comment: repcace some ifs to one expression
Use core.bitop.bsf in BitArray.opCmp for more efficient
Fix out of bounds.
std.bitmanip: BitArray.opcmp unittest improvements by MartinNowak
Merge pull request #2248 from Safety0ff/rebootpr1589

Reboot PR #1589: Fix BitArray.opCmp
Fix Issue 12921 - Module std.getopt does not respect property syntax
Make side effect on strongly pure function call
Merge pull request #2251 from 9rnsr/fix12909

Make side effect on strongly pure function call
Merge pull request #2250 from SFrijters/master

Fix Issue 12921 - Module std.getopt does not respect property syntax