[tracker] (11 commits) Non-fast-forward update to branch wip/carlosg/fix-tracker-search

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/fix-tracker-search' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  3ce5b32... libtracker-data: Add builtin way to convert a Expression to
  22ab599... libtracker-data: Convert arguments to string in string func
  4ed7a64... libtracker-data: Convert coalesced elements to string
  93e340d... tests: Add test for coalesce behavior with URNs

Commits added to the branch:

  5dd0c7c... libtracker-data: Fix crash on unbound variables in ORDER BY (*)
  ac5ba65... libtracker-data: Ensure conversion to string in topmost SEL (*)
  a0f4c09... libtracker-bus: Make cursor conform to API docs (*)
  f81c4cd... libtracker-bus: Make error clearer (*)
  3588ac6... libtracker-data: Do not force cursor column types to be str (*)
  0d37152... tests: Add test for ORDER BY an undefined variable (*)
  bc935d4... tests: Add test for resource to string casts in select argu (*)
  9d99c8a... libtracker-data: Add builtin way to convert a Expression to
  fc16c98... libtracker-data: Convert arguments to string in string func
  311f947... libtracker-data: Convert coalesced elements to string
  f0b22f5... tests: Add test for coalesce behavior with URNs

(*) This commit already existed in another branch; no separate mail sent