Refactoring for the list images tests

* Replaced assertTrue's with assertIn/assertNotIn
* Fixed pep8 issues
* Removed detailed messages for assertIn/NotIn as
  these assertions provide very detailed output

Change-Id: I04173181e7e3773392aa16b021a2febd587aebd3
Separating paging tests into own test cases

Change-Id: I015bda227d20b4d785817ec09dcf535153a279dc
refactored behavior methods

Refactored ImagesV1Behavior methods in CloudCafe.

Various changes because of change in package structure.

Change-Id: I628f9d80760b3793a6d27848429bca44458e1df1
Merge "Separating paging tests into own test cases"
Refactoring and adding paging tests

Change-Id: Icdab73dee3e17b755a2d03f556c2fe1a1e16a70b
Merge "Refactoring and adding paging tests"
Merge "Refactoring for the list images tests"