improved numerical stability on i386.

string concatenation unit tests.

because we actually have a bug!

for substrings, and the corresponding unit tests.

and add a simple unit test function.

a Set() method. Also, new HasKey() method.

I'm gonna commit this right now though I'm not really sure whether Visual
Studio will agree to build va_copy and others.

of unit tests for the String class.

computed on demand with static initialisation.

to zero.

software is installed.

functions; also remove a lot of idiotic "using namespace std" from the
codebase.

personal taste.

more unit tests for the quaternion to 3×3 matrix conversion.

mathematical writing, and add static constructors to create quaternions
from a rotation.

code for all matrices.

that are not explicitly real, even with namespace mistakes.

the matrix code itself.

that x + y != x, and nextafter() which behaves like the C function.

bonus, multiplication or division by a power of two will be optimised as
a shift of the exponent.

add the corresponding unit test.

cross product, normalize, etc.

mode, and do not call "new" when we’re not sure "delete" can be called.