Improve naming consistency

[redeboer]

Latest naming scheme from the paper draft:

	Term	Example
$\alpha$	asymmetry parameter	$\frac{2}{\Gamma}\frac{\mathrm{d}\Gamma}{\mathrm{d}\cos\theta} = 1 + P \alpha \cos\theta$
$\overline{\alpha}$	averaged polarimeter vector	$\overline{\alpha}_j = \int I_0\alpha_j \mathrm{d}^n \tau \big/ \int I_0\mathrm{d}^n \tau$
$\vec\alpha$	aligned polarimeter vector	$\vec{h} = R(\phi,\theta,\chi) \vec{\alpha}$
$\vec{h}$	polarimeter vector	$\mathrm{d} \Gamma \propto (1+ \vec{P}\cdot\vec{h}),\mathrm{d}\Phi$
$S$	scalar polarization sensitivity	$S_0^2 = 3 \int I_0 |\vec\alpha|^2 \mathrm{d}^n \tau \big/ \int I_0,\mathrm{d}^n\tau$

[mmikhasenko]

for $\alpha$, asymmetry parameter would be more accurate

[redeboer]

Also: "nominal" --> "default" (preference of LHCb)