Carve booleans library integration

==================================

Merging Carve library integration project into the trunk.

This commit switches Boolean modifier to another library which handles
mesh boolean operations in much stable and faster way, resolving old
well-known limitations of intern boolop library.

Carve is integrating as alternative interface for boolop library and
which makes it totally transparent for blender sources to switch between
old-fashioned boolop and new Carve backends.

Detailed changes in this commit:

- Integrated needed subset of Carve library sources into extern/
  Added script for re-bundling it (currently works only if repo
  was cloned by git-svn).
- Added BOP_CarveInterface for boolop library which can be used by
  Boolean modifier.
- Carve backend is enabled by default, can be disabled by WITH_BF_CARVE
  SCons option and WITH_CARVE CMake option.
- If Boost library is found in build environment it'll be used for
  unordered collections. If Boost isn't found, it'll fallback to TR1
  implementation for GCC compilers. Boost is obligatory if MSVC is used.

Tested on Linux 64bit and Windows 7 64bit.

NOTE: behavior of flat objects was changed. E.g. Plane-Sphere now gives
      plane with circle hole, not plane with semisphere. Don't think
      it's really issue because it's not actually defined behavior in
      such situations and both of ways might be useful. Since it's
      only known "regression" think it's OK to deal with it.

Details are there http://wiki.blender.org/index.php/User:Nazg-gul/CarveBooleans

Special thanks to:

- Ken Hughes: author of original carve integration patch.
- Campbell Barton: help in project development, review tests.
- Tobias Sargeant: author of Carve library, help in resolving some
                   merge stoppers, bug fixing.

CMakeLists.txt

@@ -208,6 +208,9 @@ option(WITH_LZMA          "Enable best LZMA compression, (used for pointcache)"
 # Camera/motion tracking
 option(WITH_LIBMV         "Enable libmv structure from motion library" ON)
 
+# Mesh boolean lib
+option(WITH_CARVE         "Enable Carve library to handle mesh boolean operations" ON)
+
 # Misc
 option(WITH_INPUT_NDOF "Enable NDOF input devices (SpaceNavigator and friends)" ON)
 option(WITH_RAYOPTIMIZATION	"Enable use of SIMD (SSE) optimizations for the raytracer" ON)
@@ -300,9 +303,13 @@ if(WITH_PYTHON_MODULE)
 	set(WITH_HEADLESS ON)
 endif()
 
-# auto enable openimageio and boost for cycles
+# auto enable openimageio for cycles
 if(WITH_CYCLES)
 	set(WITH_OPENIMAGEIO ON)
+endif()
+
+# auto enable boost for cycles and carve
+if(WITH_CYCLES OR WITH_CARVE)
 	set(WITH_BOOST ON)
 endif()