Let Android Studio determine debug/release build

java/jni/Application.mk

@@ -1,5 +1,5 @@
 # NDK_TOOLCHAIN_VERSION := clang3.5
 APP_STL := c++_static
-APP_CPPFLAGS := -O3 -Wall -fstack-protector -fexceptions -fno-strict-aliasing -Wno-deprecated-register -DZT_NO_TYPE_PUNNING=1
+APP_CPPFLAGS := -Wall -fstack-protector -fexceptions -fno-strict-aliasing -Wno-deprecated-register -DZT_NO_TYPE_PUNNING=1
 APP_PLATFORM := android-14
 APP_ABI := all