Changed the meaning of 'previous result' in JSON
Changed the meaning of 'previous result' in JSON

Previously, in cumulative reports the 'previous result' for each test
case meant the result from the second last time the test case was
included in a test session. However, now the previous tracks the
cumulative result of the test case regardless of whether it appears in
later sessions.

leonidas/qa-reports,leonidas/qa-reports,leonidas/qa-reports