Bland Altman Plot

%%%Plots a Bland-Altman Plot
%%%INPUTS:
%%% var1 and var2 - vectors of the measurements
%%%flag - how much you want to plot
%%% 0 = no plot
%%% 1 = just the data
%%% 2 = data and the difference and CR lines
%%% 3 = above and a linear fit
%%%
%%%OUTPUTS:
%%% means = the means of the data
%%% diffs = the raw differences
%%% meanDiff = the mean difference
%%% CR = the 2SD confidence limits
%%% linfit = the paramters for the linear fit