Blender 2.58a (64-bit)

What's new in this version:

Additions:
- More flexible size options for particle billboards. This adds scale factors for width and height of billboards, relative to the particle size. It's useful when the particle size is primarily used for collision and the like, so the billboard appearance can be adjusted independently. Also allows non-square billboards.
- In addition the billboards can be scaled by the particle velocity with optional head and tail factors (similar to line drawing options). This allows for pseudo-motionblur effects. - r37760
- Addon UI: button for removing addons which are installed to user/home paths - r37950

Python API:
Python application event handlers - r37795:
adds bpy.app.handlers which contains lists, each for an event type:
- render_pre, render_post, load_pre, load_post, save_pre, save_post
- each list item needs to be a callable object which takes 1 argument (the ID).
- callbacks are cleared on file load.
- mathutils.geometry.intersect_line_sphere(l1, l2, sphere, radius, clip=True) - r37820
- RenderEngine API: add self.report() error reporting function for render engines, works the same as for operators. - r37916

Fixes:
Essential Fixes:
- fix: Tile-able displacement map / tile-able painting regression in 2.58 - [#27782], r37899
- fix: bake crash with deep shadow, strand and children - [#27807], r37970
- fix: incorrect use of GL_ARB_vertex_buffer_object, could crash blender - r37881
- Thumbnail save for .blend crashed, when being in editmode for a mesh that has other object users as well. - [#27765], r37810
- fix: Multires lost from 2.49 file in 2.5x - [#27710,], r37837

Other Fixes:
- CMake was installing .bfont.ttf in the config dir which made updating from the previous blender version fail - r37725
- fix: Driven properties not checked for legal UI bounds - [#27726], r37744
- GHOST Cocoa: move y origin top/bottom conversions out of windowmanager module and into GHOST. Also fixes a problem where e.g. the user preferences window would not open under the mouse cursor correctly. - r37765
- revert commit 27133: Committing patch [#27133] "Fix for for Object Color in BGE" by Kupoman. This was causing a lot of backward compatibility problems and side effects. - r37773
- W special menu for changing orthographic camera lens scale was missing - r37782
- fix: Black and White Render doesn't work and/or Saves as a Blank screen, convert to grayscale when saving renders rather then only writing the red channel. - [#27746], r37783
- fix: Modal operator in Special Menu (W) ignores continues grab - [#27747], r37784
- fix: Smart UV project no longer works in 2.58 failed with active, unselected objects. - [#27742], r37785
- free_bvhtree_from_mesh was incorrectly using sizeof() when clearing memory. - r37787
- Fix undeterministic behavior of volumetric renderer - [#27748], r37802
- Made clearer in the UI that the approximate multiple scattering always enables light cache
- Fixed a potential problem in anisotropic scattering
- Default startup theme used same node header color for "in/out" nodes as for "inactive or undefined" nodes. This made it impossible to see which of the output nodes in node setup was 'active' - [#27761], r37808
- fix python errors when the sculpt brush is None - r37836
- fix for a leak in sound_read_sound_buffer(), used when drawing the sequencer waveform. - r37845
- fix: Set Bone Flags - No Scale - Toggle fails - [#27778], r37850
- fix: On clicking in a non-active Blender window (when you activated others), the mouse position of the first click was still the old position. - [#27768], r37854
- fix: Blender player on OSX not working - [#26850], r37861, r37862, r37865
- fix: Smart UV Unwrap Results in Overlaps - [#27787], r37889
- Closed regions didn't always draw the (+) icon right place, confusing for users. - r37986
- fix: foreach_get was failing on readonly properties - [#27820], r38006
- fix: Outliner does not update when parents are cleared - [#27816], r37999