[tracker] (16 commits) Created branch wip/carlosg/backports-for-3-1

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/backports-for-3-1' was created.

Summary of new commits:

  7703ef3... docs: Change lower datetime bound in doc/tests about limits
  04ee8c2... libtracker-data: Change TrackerOntology timestamp to be gin
  4fc213c... libtracker-common: Add GDateTime helper functions
  123a2d0... libtracker-data: Update ontology nrl:lastModified with GDat
  0b993d9... libtracker-data: Use GDateTime parsing for xsd:date[Time] l
  e98f4be... libtracker-data: Port datetime SQLite functions to use GDat
  cd46da3... libtracker-data: Use GDateTime on update machinery
  eddf087... tests: Remove old date/time helpers
  c9d8a1c... tests: Make TEST_TAP_ENABLED a boolean value
  842db59... Update man page reference from Tracker1 to 3
  a57c8b2... Remove leftover .1 files from manpages, should be generated
  24d0b79... libtracker-data: Do not load vtabs if vtab data is missing
  d836bec... libtracker-data: Fix parsing of first character in VARNAME 
  be2c93a... libtracker-data: Mark specific properties as being deleted
  27c624f... build: Avoid setting the regular library path in rpath
  8986ee7... tracker-data-update: remove `g_free`