format modifications in doc

get_chi2 + fit_routine restructured 

fit_routine uses Optim
LsqFit deps removed.

functions that calls uwerr now includes wpm

cdata = [[data_r1[k], data_r2[k]] for k=1:length(data_r1)]
is no longer needed

mean(rw) was computed replica by replica

compatible with old versions mesons

sum as variable

md_reader sign problem fixed

comp_t0 is generalized for polynomials of degree npol

uwerr missing
dof not reading length