Completed creation of mess form factor that supports polarized calculations; refactor: remove spaces before public, protected, private

Moved some implementations out of header file; fixed ParticleCoreShell for matrix form factor creation

Merged form factor material decorators into FormFactorDecoratorMaterial (for both matrix and scalar materials); moved matrix evaluate to IFormFactor; removed FormFactorPol

Refactor: internally store material pointers in FormFactorDecoratorScalarMaterial instead of the refractive indices

Refactor: rename form factor decorators containing material information to FormFactorDecoratorScalarMaterial and FormFactorDecoratorMatrixMaterial

Refactored FormFactor chain: transformation now sits in Particle; wavevector scattering factor and scattering density reside in the same class (FormFactorDecoratorRefractiveIndex and FormFactorDecoratorMaterial for scalar and matrix scattering respectively)

Implemented cloneInvertB() on ISample classes and use a MultiLayer with inverted magnetic field for the outgoing scattering states if necessary; refactored MagneticCoefficientsMap

Changed convention for passing two doubles to define refractive indices: now n = 1 - delta + i beta (delta, beta are the two parameters)

Added HomogeneousMagneticMaterial class to represent magnetic materials for polarized neutron scattering