Update .travis.yml for Xcode 9 and add seperate build script

Add swift build to the script

.travis.yml

@@ -1,16 +1,20 @@
-language: objective-c # lol
+language: objective-c
 osx_image: xcode9.2
 xcode_project: DVR.xcodeproj
 
-script: xcodebuild -scheme "$TRAVIS_XCODE_SCHEME" -sdk "$TRAVIS_XCODE_SDK" -destination "$DESTINATION" test
-
 matrix:
   include:
     - xcode_scheme: DVR-iOS
       xcode_sdk: iphonesimulator
       env:
-        - DESTINATION="OS=10.1,name=iPhone 7 Plus"
+       - PLATFORM="iOS Simulator,OS=11.2,name=iPhone 7 Plus"
     - xcode_scheme: DVR-macOS
       xcode_sdk: macosx
       env:
-        - DESTINATION="arch=x86_64"
+       - PLATFORM="OS X"
+    - env:
+      - SWIFT_BUILD=true
+
+script: 
+  - ./Scripts/travis-build-test.sh
+

Scripts/travis-build-test.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -x -o pipefail
+
+if [[ "$SWIFT_BUILD" == "true" ]]; then
+    swift build
+    exit 0
+fi
+
+# -jobs -- specify the number of concurrent jobs
+# `sysctl -n hw.ncpu` -- fetch number of 'logical' cores in macOS machine
+xcodebuild -jobs `sysctl -n hw.ncpu` test -project DVR.xcodeproj -scheme ${TRAVIS_XCODE_SCHEME} -sdk ${TRAVIS_XCODE_SDK} \
+  -destination "platform=${PLATFORM}" ONLY_ACTIVE_ARCH=YES CODE_SIGNING_IDENTITY="" CODE_SIGNING_REQUIRED=NO
+