yet another place we have to set the supported platform: jni/Application.mk

This fixes this warning:
 /opt/android-ndk/build/core/add-application.mk:128: Android NDK: WARNING:
 APP_PLATFORM android-14 is larger than android:minSdkVersion 8 in
 ./AndroidManifest.xml


Lame lame lame... so now it has to be set in:
AndroidManifest.xml
project.properties
jni/Application.mk