批量导入导出配置文件功能 for Swift 3

已解决冲突问题，请Merge

ShadowsocksX-NG/example-gui-config.json

@@ -0,0 +1,44 @@
+{
+    "index": 0,
+    "random": false,
+    "global": false,
+    "enabled": true,
+    "shareOverLan": false,
+    "isDefault": false,
+    "localPort": 1080,
+    "pacUrl": null,
+    "useOnlinePac": false,
+    "reconnectTimes": 3,
+    "randomAlgorithm": 0,
+    "TTL": 0,
+    "proxyEnable": false,
+    "proxyType": 0,
+    "proxyHost": null,
+    "proxyPort": 0,
+    "proxyAuthUser": null,
+    "proxyAuthPass": null,
+    "authUser": null,
+    "authPass": null,
+    "autoban": false,
+    "configs": [{
+        "remarks": "example",
+        "server": "abc.xyz",
+        "server_port": 1234,
+        "method": "rc4-md5",
+        "remarks_base64": "ZXhhbXBsZQ==",
+        "password": "passwd",
+        "tcp_over_udp": false,
+        "udp_over_tcp": false,
+        "enable": true
+    },{
+        "remarks": "example2",
+        "server": "xyz.xyz",
+        "server_port": 1234,
+        "method": "rc4-md5",
+        "remarks_base64": "ZXhhbXBsZTI=",
+        "password": "passwd",
+        "tcp_over_udp": false,
+        "udp_over_tcp": false,
+        "enable": true
+    }]
+}