[tf-2] added PIL and pandas to setup.py

[piyush01123]

Summary

I am trying to fix the tests in the tf-2 branch to make it robust with TF-2.0
Currently pytest throws 7 errors, 5 of which are import errors for libraries PIL, pandas, flaky and pyux, one is this runtime error for getting Keras backend session and the last one is this bug with pytest module.
I want to solve these one by one.
This PR solves the import errors.
2nd can be solved by removing the exception catching in that function (I checked), but would want an opinion (Because the check _is_tf_1() has been used multiple times in that script, dont know why, considering it is a tf-2 branch).
I also have a working solution for 3rd problem (remove the pytest decorators for this function)
Please let me know if I can submit those PRs as well or if I need to change my direction.

Related Issues

PR Overview

• This PR requires new unit tests [y/n] (make sure tests are included) No
• This PR requires to update the documentation [y/n] (make sure the docs are up-to-date) No
• This PR is backwards compatible [y/n] Dont know
• This PR changes the current API [y/n] (all API changes need to be approved by fchollet) No