Rename BaseAPI to APITestCase
Rename BaseCLI and MetaCLI

Rename BaseCLI to CLITestCase and MetaCLI to MetaCLITestCase
Rename BaseUI to UITestCase
Move testcase classes to robottelo.test module
Centralize logging configuration
Add docstring for robottelo.tests module.
Merge pull request #911 from elyezer/unify-test-cases

Unify test cases
Create some simple tests for path api/v2/hosts

Implement a few tests which check whether it's possible to GET the path, and add
some partially written tests for doing other things like POSTing and messing
with sub-paths of api/v2/hosts.