* Fix poll() callback changes in recent commit, note that these have
to work with pinned context too.
* Hide header for context panels in py layout.
* Don't jump back when collapsing a panel, allow the view to be
over some empty space until you scroll back.
* Fix follow context icon, order had to be reversed in icon file.
* ID template now has icon as part of browse button instead of
outside the buttons.
* Fixed some Bugs from Commit 21458.
* Show Preview Render only when there is an active id block.
* Some Code Cleanup (especially in polls). Please try to keep it clean ;-)
"moving the ID browser into its own panel. Eventually these panels should loose their headers to distinguish them from other, normal panels. Also a few other fixes for bones and armature panels."
* Fix context.cloth, was not being set correct.
* Fix errors with context pinning, scripts should
not assume context.object to be there.
* Always show preview even if e.g. the material is not
set, to keep ID buttons from jumping while you're
using them.
* Added more material buttons by William. Thanks.
I made some minor adjustments and added Specular Shader Model RNA.
* Code cleanup and some consistency tweaks of button files.
Notes: Preview render now only shows up when there is an active world, material, texture or lamp.
* Made sure initial panels with ID Datablocks are shown, even when no block is active.
* Context now allows pinning a datablock, independent of
selection.
* Initial ID browse buttons for most buttons tabs.
* Browsing from world to texture now displays world textures
again, but is a bit of a hack, not sure there is a right
way to do this.
* There's a button to switch between active materials and
textures now, only temporary though.
* There's some code to put context part in own region,
disabled still because it doesn't work that well yet.
* Fix buttons jumping around when resizing and zoom. Part of this was
adding a tiny a 0.001f offset in UI_view2d_view_ortho, otherwise the
rounding is unpredictable (used to be 0.375f, but that was disabled).
* Fix various issues with zooming, panning panels. V2D_LOCKOFS_X/Y is
now taken into account in more places in the view2d code, to avoid
zooming into the center or panning out of the view.
* Remove "Free" align mode in buttons window (it's not really useful).
* View3D/Graph/Image editors now use the same PanelType system as the
buttons window, means some deprecated panel code could be removed.
* Some small visual tweaks for panels.
* View 2D Reset operator (Home key), to reset zoom and panning for panels.
* Added argument to set number buttons as sliders (slider=True for itemR).
* Ignore labels for button alignment (doesn't look right).
* Fix some use of context.main in py scripts, should get data from active
object instead.
* Fix autotexspace -> auto_texspace in py script.
* Added new modifier tab.
* Fixed problems when no object was selected after delete.
* Added initial Armature, Bone, Curve and Font panels, by William Reynish (Billrey). Thanks!
* Small RNA changes
* Commit revision 20240 and 20268 from trunk. ("Mouse wheel zoom lost after rendering.")
