GUIrenderer: add oglSquelchError
lib.h: add feq() (checks for floating point equality); remove redundant
if from SAFE_DELETE
maths: use new feq()
Model*RData, VertexArray: fix trivial warnings
This was SVN commit r2904.
squelch debug asserts during self-tests to avoid warning about intended
errors (passing invalid data into functions to test their error
reporting)
This was SVN commit r2646.