[gegl] (13 commits) Created branch threaded-base-classes

[Øyvind Kolås <ok src gnome org>]

The branch 'threaded-base-classes' was created.

Summary of new commits:

  e893b51... Make GeglOperation base classes threadable
  622d017... op-point-composer3: make don't override parent class' proce
  9b09262... operation-composer3: bail earlier on 0x0 roi
  f82d1c7... buffer: hold tile cow mutex only when updating linked list
  8b9fd70... XXX: do not commit, buffer: do not use hot tile
  d1f7466... opt point-composer3 ops out of parallelization
  2b2ab5e... operation: refactor in_place handling to take place in base
  0da7ef5... tile_handler_cache: add debug print and bail if tile==NULL
  882d1aa... tile: lock shuffling
  bbfcb9d... buffer: use tile-indice based mutexes for tile-writing
  d6fc314... operation: make default parallelization be for point-render
  6796664... ops: opt ops out of parallelization
  e25e7d0... factor out check if threading should be used