Update to glew 1.10.0 for the mac builds.

Note: other builds may want to test to ensure that they do not build against glew 1.9.0 since it can cause crashes.
Fix the SDKROOT setting in sub projects.

Update xcode 4+ project files.
Update png to 1.5.17.
Fix ups.

 * Add underscore.sty into 3rdparty
 * Use a quoted here doc in CS-ID
 * Try not to blowup quite so spectacularly building the docs without a network connection.
Update the xcode project file to the 3.2 format.
Merge branch 'bugfixes'

* bugfixes:
  Update the xcode project file to the 3.2 format.
  Fix ups.
  Update png to 1.5.17.
  Update to glew 1.10.0 for the mac builds.