doc: Use AMS's align instead of eqnarray.

This is the recommended environment due to spacing differences between
eqnarray and normal equations.
Update Inria spelling.

The official guidelines [1] state "Inria" must be capitalized this way
and not "INRIA", in all cases.

[1] https://www.inria.fr/en/content/view/full/11296
doc: Remove duplicate/unused logos.
doc: Spelling and grammar fixes.