add acknowledgment & license of zlib

LICENSE.TXT

@@ -150,6 +150,33 @@ limitations under the License.
 
 
 
+Open Source Software Licensed Under the zlib License: 
+The below software in this distribution may have been modified by THL A29 Limited (“Tencent Modifications”). All Tencent Modifications are Copyright (C) 2018 THL A29 Limited.
+----------------------------------------------------------------------------------------
+1. zlib  v1.2.11
+Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
+
+Terms of the zlib License:
+--------------------------------------------------------------------
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+
+
+
 Terms of the BSD 3-Clause License:
 --------------------------------------------------------------------