Added new environment management tool for the tests. This way, the tests
will be able to use more generic code, and network parameters such as
IP/MAC addresses will not have to be hard-coded.Added new tool.
`env_management.py` is now fully integrated in the test framework.
Merge pull request #1 from drimer/tests_config

Merged `tests_config`: This work is important because it will make the tests completely configurable just by editing a text file. For the time being, it is not necessary, but when more tests are written and sniffing data from the network and some parameters have to be hard-coded, with this tool only the "alias" of the devices will have to be used.