Add the `doc` to the `resource`.
Merge pull request #51 from guori12321/patch-1

Add the `doc` to the `resource`.
upgrade desc of doc
warning msg
expand and short an url (short is just for sina)
add renren and tencent short url UT
add imports
1) deal with invalid URL 2) format: tab -> blanks
Merge branch 'master' into dev
add contributor