1.add timeout parameter for every http method, default timeout value is 2
seconds.
2.now both post and put request support default none body parameter.
3.add expect return value for test case add_property_to_node.

Signed-off-by: Denghui Huang <huangdenghui@gmail.com>
Merge branch 'master' of github.com:yeasy/CSIT_Test

Conflicts:
	base/cases/switch_manager.py

Signed-off-by: Denghui Huang <huangdenghui@gmail.com>