Modify the iotdm library and add add test cases

Modify the iotdm library and add add test cases

Modfify ciotdm.py and criotdm.py to meet the requirements.
Add 5 robot files under iotdm basic folder.

Signed-off-by: Cangji Wu <canwu@cisco.com>
Signed-off-by: Jamo Luhrsen <james.luhrsen@hp.com>
Add 2 libraries and one more test suite

Criotdm is based on ciotdm. And ciotdm is based on iotdm library.
Both libraries follow pep8 and pep257.
For test suites, modify a lot of duplicate code into keyword.
Remove the invalid elapse method in test cases.
Delete the useless 020 test suite.
Comment some test cases to let all the test cases pass.
Remove unused "time" in the criotdm library.

Change-Id: Idcdd4bd378a2b92c495ee1f7f4d6cb20631582ad
Signed-off-by: Cangji Wu <canwu@cisco.com>