Blender 2.57b (64-bit)

What's new in this version:

Essential Fixes:
- fix crash when pressing Enter on menu item which load a file: Ctrl+N,Enter or Ctrl+O,Enter r36287
- fix crash appending/linking objects #27158, r36313
- fix crash for files saved with file selector open r36321
- fix crash with edge split modifier #26993, r36330
- fix for numerous cases where material links would be lost when making object data local #27178, r36332
- fix for crash getting the vertex weight from object types which don't support this vertex groups. r36291

Rendering:
- fixed a memory leak on canceling bake r36284
- fix for memory leak with node group members that have multiple ouputs some of which are unused #27104, r36290
- fix for node socket bug which lead to incorrect black/white output levels r36306
- fix 3d text and simple deform modifier giving bad results #27048, r36301
- fix for boid particles getting Z clamped to 0.0 when "Allow Flighting" is on. #27112, r36325

Tools:
- fix changing selected shapekeys in editmode causing badly deformed keys #26959, r36296
- mesh.dupli_extrude_cursor (Ctrl+Click extrude), failed when the selected vertex was behind the view #27091, r36279
- fix all mesh normals being recalculated when adding meshes in editmode #27121, 36323
- skip displace modifier when no changes are needed r36319
- setting subsurf with Ctrl+1/2/3/4 now works in editmode too. #27126, r36299

Python:
- fix for crash exporting Collada files to an invalid path #27162, r36326
- RegionView3D.view_rotation was inverted, view_matrix is now writeable r36317

Interface:
- slider widget was showing strange colors with some themes #27139, r36324
- fix for text editor syntax highlighting glitch when changing tab width. r36294

Additions:
- added support for sculpting on blended shape keys r36295
- new view 'dolly', zoom which moves the view port forward in perspective mode, not restricted by the view rotational pivot. (Ctrl+Shift+MMB). r36283
- continuous zoom now uses dolly settings for horizontal/vertical mouse & inverted movement.
- convenience button in modifiers panels to allow switching to the physics tab r36327

Blender Addons:
Unreal Engine Format:
- fixed error on export single/all/select action sets.
- added weight when import into blender and filter out the ext.

OBJ Format:
- fixed importing OBJ groups as vertex groups. [#27149], r1865
- fresnel setting was broken on import [#27170], r1869
- importing vertex order was not maintained (added option back) [#27145], r1867

- Povray Render Support: Detect povray binary on unix.
- DirectX Export: Improved phong shader setting. r1871