Bounding volumes improvements

- Simplified BoundingFrustum implementation
- Added implementation for BoudingFrustum.Intersects(BoundingSphere)
Fix iOS build

- missing using statement
Improve render states support for OpenGL / OpenGLES
Fix SamplerState (OpenGL)

- Fixed texture target typo
- Added proper boundary check for MaxAnisotropy
Fix EffectParameter.SetValue(Texture)

- EffectParameter.SetValue(Texture) shouldn't throw an exception when passing null (XNA 4.0 doesn't)
Fix WindowsGL build
Merge pull request #1378 from flyingdevelopmentstudio/develop3d

iOS render states + build fixes