Fix bug 4928: [Search] Journal note hits not shown

- Added tests and specs for bug #4928
- Examined bug
  - Added debug output to examine event contents
  - Examined journals
- Added highlight_first helper
  - Used last_journal instead of #journals.last
  - Fixed Journalized#last_journal to work when eager loading messed up search
  - Fixed how journals are sorted when they are loaded (by version instead
    of created_at)
- Added notes anchor when required
  - Added notes anchor when required
  - Note anchor uses version of journal note itself, not version of work package
- Fixed failed test in
  functional/wiki_controlller_test.rb:WikiControllerTest
  #test_update_stale_page_should_not_raise_an_error
- Fixed failed specs.
- Converted search helper test -> spec, removed test file.
- Re-factored regexps in search controller, covered them with specs.
- Temporary added job for travis to run isolated suite
  work_package_activity_provider_spec
- Suite work_package_activity_provider_spec ran successfully - removed note and job.