public void setLastPath(String lastPath) {
        if (Gdx.files.absolute(lastPath).exists()) {
            generalPref.putString("last-path", lastPath);
            generalPref.flush();
        }
    }
Checks every drawable path for existence. Errors are reported as a list
of DrawableDatas.
@return A list of all DrawableDatas that must have their paths resolved.
Returns an empty list if there are no errors.
core/src/com/ray3k/skincomposer/data/ProjectData.java