Modified LauRhoOmegaMix to allow either a RelBW or GS lineshape for the rho, as well as   allowing the option to set the second-order denominator term to be equal to unity.   Also fixed the bug where the spinTerm was not included in the rho-omega amplitude.   Changed the LauAbsResonance enum from RhoOmegaMix to RhoOmegaMix_GS, RhoOmegaMix_RBW,   RhoOmegaMix_GS_1 and RhoOmegaMix_RBW_1, where _1 sets the denominator term to unity and   _GS or _RBW sets the appropriate rho lineshape. The omega is always a RelBW.

Added to LauAbsResonance: ignoreSpin and ignoreBarrierScaling boolean flags, which ignore
either the spin terms or the barrier scaling factors for the amplitude. The latter does not 
turn off the resonance barrier factor for mass-dependent widths

Added to LauResonanceMaker: getResInfo(resonanceName), which retrieves the resonance information.
This is used to obtain the PDG omega values for initialising LauRhoOmegaMix

Made LauRelBreitWignerRes ignore momentum-dependent terms for the resonance width if ignoreMomenta is set.
This is used in the LauRhoOmegaMix for the omega lineshape where its width does not depend on momentum