Function for fixing duplicated timestamps in generated RSS feed
Unit test for function, which fixes duplicated timestamps issue
Refactoring + get rid of passing arguments by reference (because of troubles with testing the function via reflection)
Changed mock in such way, that it will be able to test function processItems separately from fixDuplicatedTimestamps
Refactoring: renamed few variables in test
Reformatted code
Added comment to function
Improved unit test by using small part of real data
Reformatting the code
Refactoring due to remarks from code review
Added tests for created methods
Merge branch 'dev' into fix_rss_timestamps_PLA-1622

Conflicts:
	extensions/wikia/HubRssFeed/tests/models/BaseRssModelTest.php
Merge pull request #3981 from Wikia/fix_rss_timestamps_PLA-1622

Avoid duplicating of timestamps in generated RSS (PLA-1622)