Merge pull request httprunner#475 from HttpRunner/2.0

Release 2.0.0

Merge pull request httprunner#427 from HttpRunner/locusts

refactor locusts

release 1.4.0

Validate JSON testset format

release 1.2.3

update version

refactor parameterization:

parameter value now can be in three types:
(1) data list
(2) call built-in parameterize function
(3) call custom function in debugtalk.py

add setup.py upload support