implement 1.9.14 changed api interface - getTestCaseKeywords

[lczub]

the interface of api method getTestCaseKeywords, introduced with TL 1.9.13, will change with TL 1.9.14

• TL 1.9.13 one arg: or
  must be called for each test case separately

• TL 1.9.14 one args: <set of or >
  can be called for a set of test cases

  related TL Mantis Task

• 6931: [API - XMLRPC] Get keywords changed to support test case set as input

[lczub]

Travis reports a broken build for #53.

reason is, that also the error code behaviour for getTestCaseKeywords has changed for the situation invalid test case id:

• 1.9.13 error code - 5000
• 1.9.14 error code - 5040

Unit tests test_getTestCaseKeywords_unknownID are already adapted, but the used testlink demo application is still representing a 1.9.13 dev state from 26/12/14.

So all 1.9.14 related unit test needs a @unittest.expectedFailure decorator like test_addTestCaseKeywords_unknownID

[lczub]

changed tests passed travis build