use auto return in std.datetime
std.array: clean imports

assocArray: updated doc header.

add scope import

added global import in std.array

global import std.algorithm : splitter; in std.arra;

update splitter

import typetuple

import std.algorithm

Fix split

import std.algorithm fix
Merge pull request #2673 from 9il/array

std.array: clean imports
Merge pull request #2689 from WalterBright/toauto

[blocker fix]: use auto return in std.datetime
issue 13717

https://issues.dlang.org/show_bug.cgi?id=13717
Merge pull request #2692 from 9il/issue13717

fix issue 13717