added keyword parameter 'replica' to corr_obs(cdata::CData,...) for consinstency with corr_obs(cdata::Array{CData,1}...)

pvalue function for uncorrelated data now accept a W vector. default value is Vector{Float64}(), and if W is not provided, it is computed as the inverse of the error squared of the data.

Added new versions of plat_av. now the function accept a optional vector or a matrix of weight. wpm is still an optional paramter for backward compatibily.

Finalizing the merging

See merge request !3

Julien's most updated code has all valence derivatives with the sign changed, so md_val needs to flip the sign. Also, the reader does not write "_d1, _d2" in the derivatives anymore for the new data files, so md_val does not look for "_d1, _d2". You need to select by hand which correlators are your valence derivatives, looking at the log file e.g.

Updated dec_const to use plot_data and plot_func, added optional return for fig and ax objects, updated documentation

Updated meff to use plot_data and plot_func. Now the function output also fig,ax if pl is true. Updated documentation

Updated mpcac function using plot_data and plot_func, added overload for Vector{Corr}, added optional return to plot obj, updated documentation