Added initial Smoothed Particle Hydrodynamics implementation (SPH), for CPU and CUDA.

This software is contributed under the ZLib license by Rama Hoetzlein, http://www.rchoetzlein.com
We plan to integrate the SPH into the core Bullet library, including interaction with rigid bodies and soft bodies.

Extras/sph/READ_ME.txt

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+
+FLUIDS v.1 - SPH Fluid Simulator for CPU and GPU
+Copyright (C) 2008. Rama Hoetzlein, http://www.rchoetzlein.com
+
+A fast CPU and GPU fluid simulator. See website above for details.
+
+Notes 
+(April 2009)
+-------------------
+
+- Press 'h' for help screen. This shows keyboard cmds available.
+
+- By default, GPU simulation is off.
+  When running the fluid_gpu.exe, press 'g' to start/stop GPU simulation.
+
+- Disabling shadows in common_defs.h will greatly speed up the simulation
+  (You can also press 's' to render without shadows)
+
+- As of April 2009, CUDA builds only under Visual Studio 2005, not VS 2008.
+  To enable the CUDA build in VS2005, set the BUILD_CUDA define in common_defs.h
+  Be sure this is turned off if you build with VS2008.
+
+- The GPU integrator is not yet complete. Integration always takes place on the CPU, in both CPU and GPU modes. (As a result, this forces a bus transfer to and from the GPU per cycle. Once the integrator is finished, GPU simulation performance should increase significantly.)
+
+- Occassionally, the GPU simulation with crash cuda, causing the screen to blink and particles to move randomly. This is believed to be due to a not-yet-found out of bounds condition.
+
+ZLib License
+-------------------
+This software is provided 'as-is', without any express or implied  warranty.  In no event will the authors be held liable for any damages arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.