Fixed crash associated with .osg files which contain empty description fields.
From Sondra Inverson, added support to .ive plugin for osgSim::DOFTransform.
value to float, and converted the internal code across to use value_type. This
allows Matrix to be converted to use double's simply by change the definition
of value_type. Added Matrix::glLoadlMatrix and Matrix::glMultMatrix() to
help encapsulate the changes between float and double matrix usage.
Updated code that uses Matrix so it doesn't assume float or double matrices.
email from Marco)
"Most relevant news:
1) particle systems now have the "freezeOnCull" property set to false by
default. Since it is an optimization, and using it may cause some unwanted
behaviors if not handled properly, it makes more sense to turn it off by
default.
2) new "LINE" shape mode which uses GL_LINES to draw line segments that
point to the direction of motion.
3) particles can now have a rotation angle and angular velocity.
4) new AngularAccelOperator applies angular acceleration to particles.
5) particle processors such as emitters and programs can have a "start",
"end" and "reset" time coordinate. For example, an emitter may be instructed
to start emitting particles only after a certain time, stop after another
amount of time and then start again.
Update (2) is from Gideon May.
Updates (3) to (5) are from Douglas A. Pouk."
