[tracker] (7 commits) ...libtracker-data, tracker-store: Make statement cache sizes configurable with env var

[Philip Van Hoof <pvanhoof src gnome org>]

Summary of changes:

  bf6987a... libtracker-data: Don't cache stmt if the query contains a r (*)
  6679fda... libtracker-data: LRU ring for the TrackerDBStatement cache (*)
  32a4b6d... libtracker-data: Different LRU-cache for INSERT/DELETE v. S (*)
  417dee4... libtracker-data, -direct, tests: Make it possible to set th (*)
  719e2ad... libtracker-data: Fix crash when first query thread is creat (*)
  f8872fe... tracker-store: Use private threads for the query thread poo (*)
  34194e7... libtracker-data, tracker-store: Make statement cache sizes  (*)

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