Update NDK version to r10e, OSX support

builds/qt-android/ci_build.sh

 #!/usr/bin/env bash
 
+NDK_VER=android-ndk-r10e
+
+if [ $TRAVIS_OS_NAME == "linux" ]
+then
+    NDK_PLATFORM=linux-x86_64
+elif [ $TRAVIS_OS_NAME == "osx" ]
+then
+    NDK_PLATFORM=darwin-x86_64
+else
+    echo "Unsupported platform $TRAVIS_OS_NAME"
+    exit 1
+fi
+
+export FILENAME=$NDK_VER-$NDK_PLATFORM.bin
+
 (cd '/tmp' \
-    && wget http://dl.google.com/android/ndk/android-ndk-r9-linux-x86_64.tar.bz2 \
-    && tar -xf android-ndk-r9-linux-x86_64.tar.bz2 \
-    && mv android-ndk-r9 android-ndk)
+    && wget http://dl.google.com/android/ndk/$FILENAME \
+    && chmod a+x $FILENAME \
+    && ./$FILENAME &> /dev/null ) || exit 1
+unset FILENAME
 
-export ANDROID_NDK_ROOT="/tmp/android-ndk"
-export TOOLCHAIN_PATH="/tmp/android-ndk/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin"
+export ANDROID_NDK_ROOT="/tmp/$NDK_VER"
+export TOOLCHAIN_PATH="$ANDROID_NDK_ROOT/toolchains/arm-linux-androideabi-4.8/prebuilt/$NDK_PLATFORM/bin"
 export TOOLCHAIN_NAME="arm-linux-androideabi-4.8"
 export TOOLCHAIN_HOST="arm-linux-androideabi"
 export TOOLCHAIN_ARCH="arm"