added ndk installation script

.travis.yml

@@ -36,10 +36,10 @@ addons:
       - python2.7
       - libmagic1
 
-before_script:
+before_install:
+  - ./scripts/install_android_ndk.sh
   - export PATH=$HOME/.local/bin:$PATH
-  - pip install -r ./scripts/requirements.txt --user
-
+  - pip install -r ./configs/requirements.txt --user
 
 script: ./gradlew build --no-daemon
 

scripts/install_android_ndk.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+if [ `uname -m` = x86_64 ];
+then
+    wget http://dl.google.com/android/ndk/android-ndk-r10d-linux-x86_64.bin -O ndk.bin
+else
+    wget http://dl.google.com/android/ndk/android-ndk-r10d-linux-x86.bin -O ndk.bin
+fi
+
+7z x ndk.bin android-ndk-r10e/build/ android-ndk-r10e/ndk-build android-ndk-r10e/platforms/android-21 > /dev/null
+export ANDROID_NDK_HOME=`pwd`/android-ndk-r10e
+echo "ndk.dir=$ANDROID_NDK_HOME" >> local.properties