std_df: Create a data frame of all standards
In LCF: Linear Combination Fitting

The function creates a data frame with all standards in one data frame. The data frame has the same energy values as the sample that is loaded.

1	std_df(sample, all.standards)

`sample`	A raw sample
`all.standards`	List of all standards

data(stdmix)
corr.spec.standards  <- initial_load(specdat[1:4], 
  corr.norm = c(-36, -15, 37, 58))
corr.spec.samples    <- initial_load(specdat[5:8], 
  corr.norm = c(-36, -15, 37, 58))
fit.standards <- std_df(sample = corr.spec.samples[[1]], 
  all.standards = corr.spec.standards)
print(fit.standards)