[cogl] (12 commits) Created branch wip/for-cairo-cogl

[Robert Bragg <rbragg src gnome org>]

The branch 'wip/for-cairo-cogl' was created.

Summary of new commits:

  ebdb77b... framebuffer: Add explicit buffer discard API
  1390910... Rework how we search for winsys configs
  5a6452a... onscreen: Support point sample based onscreen rendering
  6791e76... offscreen: Adds support for offscreen multisampling
  9b252b4... examples: Adds a simple 4x msaa example
  68e31cb... Add a strong CoglTexture type to replace CoglHandle
  bdfb15f... framebuffer: associate tex with fb after Object init
  5e4c053... attributes: avoid g_strdup in cogl_attribute_new
  0d6542d... primitive: micro optimize primitive allocations
  3504134... attributes: optimize validation of tex_coord%d_in names
  b350fcf... pipeline: lazily get ctx in _get_layer
  0f55c21... pipeline: optimize _compare_differences functions