use generic multiplication when computing derivative
compute the order of a prime appearing in a rational
start an interface for working with (exponential) valuations
rename value comparahandle the value infinity (for valuations)
indicate the reliability of the valuation value
alternative view of valuations, where we look at all coefficients separately
move infinity to generic-math
move infinity to its own file (it's soo big!)
add some infinite arithmetic required by poly formatting code
fix inf symbol in val-coeff