#301 Support for saving meshes as B3D with support for animation

[Christian Clavet]

Here is the patch for the B3D Animated mesh saver. (Original patch made by Hendu, then modified JLouisB to support saving of animations and bones.)
Check the thread here for details:
http://irrlicht.sourceforge.net/forum/viewtopic.php?f=2&t=50067&p=291690#p291690

[Michael Zeilfelder]

I made some modifications. We can't use dynamic_cast as Irrlicht is compiled without rtti. So I moved the getMeshType interface from IAnimatedMesh up to IMesh and check for EAMT_SKINNED instead.
Also some Irrlichtification (upper-case member-variables).
And let b3d loader also use the new structs file.
But having one problem - it doesn't work. My test is here: https://code.google.com/p/irr-playground-micha/source/browse/b3d_readwrite.cpp

[Michael Zeilfelder]

Got applied to svn trunk in r5095