Some extra packages for OpenWrt

Add "src-git extra git:https://github.com/shangjiyu/openwrt-extra.git" to feeds.conf.default.

./scripts/feeds update -a
./scripts/feeds install -a

the list of packages:

• dnscrypt-proxy
• dns2socks
• chinadns
• luci-app-aira2
• shadowsocks-libev
• webui-aria2
• yaaw
• ShanXun (sxplugin-singleNet)
• yixun
• Dr.COM (ZJUT only)
• Node.js (untested)
• mentohust
• ChinaDNS
• ShadowVPN
• REDSOCKS2
• deadwood
• adkill
• adbyby-mt7620
• gargoyle
• exfat-fuse
• exfat-nofuse
• n2n_v2
• ngrokc
• shellsync
• subversion
• tengine
• vlmcsd
• xsocks

• luci-app-vlmcsd