Gets the build time of the Android app. Thanks to: http://stackoverflow.com/a/7608719/382130

gistfile1.java

String getBuildTime() throws NameNotFoundException, IOException {
	ApplicationInfo ai = getPackageManager().getApplicationInfo(getPackageName(), 0);
	ZipFile zf = new ZipFile(ai.sourceDir);
	long time = zf.getEntry("classes.dex").getTime();
	zf.close();
	return new SimpleDateFormat("yyyy-MM-dd h:mm:ss a zzz").format(new Date(time));
}