pd_rescale: Function for rescaling coordinates.
In nenaoana/MDScosa: Multidimensional Scaling (MDS) for COSA data

Function for rescaling the coordinates obtained with pd_mdsmat and pd_pscale.

pd_rescale <- (mdsmat, 
 distmat, 
 n_issues, 
 n_years)

`mdsmat`	Distance and weight matrices. Usually the result of function pd_mdsmat.
`distmat`	Matrix of distances and coordinates. Usually the result of pd_pscale.
`n_issues`	Number of issues left after deletion with the pd_mdsmat function.
`n_years`	Number of years.