add active directory support

Fix #1609

version to 1.2.0-SNAPSHOT

shutting down the demo server, temporarily.

Block delete default cluster

Support to override meta server url through environment variables.

commit 49a8bd839e1f13c0c3b91f8d314dd4cb3fca1e3e
Merge: 211848897 e34cdce4f
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sun Oct 14 12:33:46 2018 +0800

    Merge branch 'master' of https://github.com/JaredTan95/apollo

commit 2118488976059333c8e4c006d98cb37d81097a11
Author: nobodyiam <nobodyiam@gmail.com>
Date:   Sat Oct 13 16:49:39 2018 +0800

    version to 1.1.1

    clean code.

    fix code style.

commit 9e32fcc48b8c7dfbc3c3869ccc81091a0890a02a
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sat Oct 13 14:51:20 2018 +0800

    Support to override meta server url through environment variables.

commit e34cdce4f33528690deec7c3660dba514c3aeaef
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sun Oct 14 09:35:35 2018 +0800

    fix code style.

commit 58e6fc7eef58f9623eb542c255ded0da59bb0852
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sat Oct 13 20:15:38 2018 +0800

    clean code.

commit a7fcbecdec389215ea9ad73db627e1cb2d425f41
Merge: 15532fdf9 c22ac563
Author: Jared.Tan <jian.tan@daocloud.io>
Date:   Sat Oct 13 17:25:14 2018 +0800

    Merge branch 'master' into master

commit 15532fdf9ecb703f21f4f743a4651b6ae003f24c
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sat Oct 13 17:23:27 2018 +0800

    refactoring legacy mete server and fix mistake in Dockerfile.

commit 3c9b00e24df47ee42a74771aa94fd2c383084b30
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sat Oct 13 16:37:04 2018 +0800

    modify Dockerfile Env `Version` to prevent duplicate changes and errors

commit 9ec44a8954460ae72aa27300ea519e2d0c99f470
Author: JaredTan95 <jian.tan@daocloud.io>
Date:   Sat Oct 13 14:51:20 2018 +0800

    Support to override meta server url through environment variables.

version to 1.1.1

rollback spring boot maven plugin version to 1.3.5.RELEASE

version to 1.1.1-SNAPSHOT

version to 1.1.0

adjust cache control so that entry htmls are not cached, as we need them to trigger 302 in case user is not logged in

adjust cache control so that entry htmls are not cached, as we need them to trigger 302 in case user is not logged in

Manually stick spring boot to 1.5.x for apollo-client, so that we could compile apollo-client against Java 7

Manually stick spring boot to 1.5.x for apollo-client, so that we could compile apollo-client against Java 7

refactor gray release open api a little bit