Update to swift 2.3

Also set test env to Xcode 8.

.travis.yml

@@ -1,11 +1,12 @@
 language: objective-c
-osx_image: xcode7.3
+osx_image: xcode8
+
+install:
+  - gem install gym
 
 script:
-- xctool -project tun2socks.xcodeproj -scheme "tun2socks-macOS" -sdk macosx10.11 -arch
-  x86_64 build
-- xctool -project tun2socks.xcodeproj -scheme "tun2socks-iOS" -sdk iphoneos9.3 -arch
-  arm64 build CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO
+- xcodebuild -project tun2socks.xcodeproj -scheme "tun2socks-macOS" | xcpretty
+- xcodebuild -project tun2socks.xcodeproj -scheme "tun2socks-iOS" | xcpretty
 
 after_success:
 - "./docs/build_docs.sh"

tun2socks.xcodeproj/project.pbxproj

@@ -872,15 +872,19 @@
 				TargetAttributes = {
 					3642C9FD1CEDCC60001E0AAF = {
 						CreatedOnToolsVersion = 7.3.1;
+						LastSwiftMigration = 0800;
 					};
 					36A718F01D5B0A1B00DC35F5 = {
 						CreatedOnToolsVersion = 7.3.1;
+						LastSwiftMigration = 0800;
 					};
 					36A718FE1D5B0AC100DC35F5 = {
 						CreatedOnToolsVersion = 7.3.1;
+						LastSwiftMigration = 0800;
 					};
 					36C48CA11CF8701A0071804F = {
 						CreatedOnToolsVersion = 7.3.1;
+						LastSwiftMigration = 0800;
 					};
 				};
 			};
@@ -1130,6 +1134,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = me.zhuhaow.osx.tun2socks;
 				PRODUCT_NAME = "$(PROJECT_NAME)";
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Debug;
 		};
@@ -1149,6 +1154,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = me.zhuhaow.osx.tun2socks;
 				PRODUCT_NAME = "$(PROJECT_NAME)";
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 			};
 			name = Release;
 		};
@@ -1168,6 +1174,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = me.zhuhaow.osx.lwip;
 				PRODUCT_NAME = lwip;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 				USER_HEADER_SEARCH_PATHS = "$(SRCROOT)/lwip";
 			};
 			name = Debug;
@@ -1188,6 +1195,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = me.zhuhaow.osx.lwip;
 				PRODUCT_NAME = lwip;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 				USER_HEADER_SEARCH_PATHS = "$(SRCROOT)/lwip";
 			};
 			name = Release;
@@ -1209,6 +1217,7 @@
 				PRODUCT_NAME = lwip;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				USER_HEADER_SEARCH_PATHS = "$(SRCROOT)/lwip/";
 			};
@@ -1231,6 +1240,7 @@
 				PRODUCT_NAME = lwip;
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				USER_HEADER_SEARCH_PATHS = "$(SRCROOT)/lwip/";
 				VALIDATE_PRODUCT = YES;
@@ -1255,6 +1265,7 @@
 				PRODUCT_NAME = "$(PROJECT_NAME)";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -1277,6 +1288,7 @@
 				PRODUCT_NAME = "$(PROJECT_NAME)";
 				SDKROOT = iphoneos;
 				SKIP_INSTALL = YES;
+				SWIFT_VERSION = 2.3;
 				TARGETED_DEVICE_FAMILY = "1,2";
 				VALIDATE_PRODUCT = YES;
 			};

tun2socks/TSIPStack.swift

@@ -35,7 +35,7 @@ public final class TSIPStack {
     public static var stack = TSIPStack()
 
     // The whole stack is running in this dispatch queue.
-    let processQueue = dispatch_queue_create("tun2socks.IPStackQueue", DISPATCH_QUEUE_SERIAL)!
+    let processQueue = dispatch_queue_create("tun2socks.IPStackQueue", DISPATCH_QUEUE_SERIAL)
 
     var timer: dispatch_source_t?
     let listenPCB: UnsafeMutablePointer<tcp_pcb>