Merge pull request #1 from biaobiaoqi/master

Thanks biaobiaoqi's contribution.
add sync posts before date
fix img[src] is nil
add sync post by title method
Merge pull request #3 from zhaozhiming/master

add sync posts before date
make sync all posts from earliest to lastest
change before date task to after date task
refactor code
Merge pull request #4 from zhaozhiming/master

add some function and refactor code