Different root isolation algorithms now live in separate modules,
and are all instances of the RootIsolationAlgorithm typeclass.
This separates the algorithmic code from the top-level driver code
in Math.Root.Isolation.
Computing a rotation in interval arithmetic can lose tightness.
Instead of computing
a cos phi + b sin phi
which doesn't account for the difference in phase in the two sinusoids,
it is better to use
sqrt (a² + b²) * cos ( phi - atan2(a,b) )
which correctly estimates the maximum amplitude of the sum to be
sqrt(a²+b²) instead of abs(a) + abs(b).
This seems to worsen the performance of the interval Newton method
at the moment, possibly due to the complexity of the new formula,
which involves computing atan(b/a). Further investigation is needed.
also includes the start of a way to observe which equations
are being solved, which should help with improving the performance of
the interval Newton method
* each stroke stores the brushes it uses by reference,
so that one can interactively edit brushes
and see the strokes be updated in real-time
* when writing to a file, we retrive the brush code
from the reference, and include that information statically
* use PrimArray to represent polynomials
* add some strictness annotations
* turn on some optimisation flags
* use quadratic formula for quadratic polynomials