Add onGameTick20 to try and encourage lua to be a bit more efficient. Rewrite Space Invasion to use it. Top speed of aliens is 25% higher now, although that could be changed, I kinda liked it. Change parameter order of div().
MISC_DIR := $(call my-dir)
LOCAL_PATH := MISC_DIR
include $(MISC_DIR)/libfreetype/Android.mk
include $(MISC_DIR)/liblua/Android.mk
include $(MISC_DIR)/libtremor/Android.mk