OpenWrt安装Passwall
官方给的安装文档太过精简，缺少必要的东西，补充一下
1.安装前请先在openwrt弄好梯子，保证可以访问sourceforge
2.更换openwrt默认带的dnsmasq到dnsmasq_full版本：
opkg update opkg remove dnsmasq opkg install dnsmasq_full
3.新增opkg key
wget -O passwall.pub https://master.dl.sourceforge.net/project/openwrt-passwall-build/passwall.pub opkg-key add passwall.pub
4.添加稳定版仓库
read release arch << EOF
$(. /etc/openwrt_release ; echo ${DISTRIB_RELEASE%.*} $DISTRIB_ARCH)
EOF
for feed in passwall_luci passwall_packages passwall2; do
echo "src/gz $feed https://master.dl.sourceforge.net/project/openwrt-passwall-build/releases/packages-$release/$arch/$feed" >> /etc/opkg/customfeeds.conf
done5.开始安装passwall
opkg update opkg install luci-app-passwall
