Move campaign mission images to share/ instead of hardcoding them into frontend
Hardcoding campaign mission images prevented add-ons from adding their own preview images.
MISC_DIR := $(call my-dir)
LOCAL_PATH := MISC_DIR
include $(MISC_DIR)/liblua/Android.mk
include $(MISC_DIR)/libphysfs/Android.mk
include $(MISC_DIR)/libphyslayer/Android.mk