replace casperjs with selenium
clean up test code
[tests] add account api test
[tests] add api test for group members, groups, group msgs, user msgs
[tests] add web api test for avatar service
[tests] add web api test for miscs
[tests] add web api test for libraries
disable CheckOrCreateSublibrary test temporarily
[tests] add web api test for files
[tests] add web api test for directories
[tests] add the rest of web api test
[tests] follow python codestyle
Merge pull request #271 from Chilledheart/master

replace casperjs with selenium