ndk+ci: Upgrade to use CrystaX NDK 10.3.1 and a more recent version of Crypto++ library

This commit also fixes checks with Travis-CI that were effectively broken before.

Change-Id: Ibf9e54de47db00ed01534187a19a3d40e9dee84e
diff --git a/app/src/main/jni/Application.mk b/app/src/main/jni/Application.mk
index 121e000..976b943 100644
--- a/app/src/main/jni/Application.mk
+++ b/app/src/main/jni/Application.mk
@@ -1,5 +1,7 @@
 APP_ABI := all
 
 APP_STL := gnustl_shared
-APP_GNUSTL_FORCE_CPP_FEATURES := exceptions rtti
+APP_CPPFLAGS += -fexceptions -frtti -std=c++11 -Wno-deprecated-declarations
 
+NDK_TOOLCHAIN_VERSION := 5
+APP_PLATFORM := android-19