Removed unused ZLib files

	deleted:    src/SharpGIS.GZipWebClient/ZLib/Crc32.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/FlushType.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/GZipStream.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/InfTree.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/Inflate.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/ZLib.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/ZLibCodec.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/ZLibConstants.cs
	deleted:    src/SharpGIS.GZipWebClient/ZLib/ZLibStream.cs