read_vpts should validate type of each parameter

[adokter]

Function validate_vpts() currently doesn't validate the return type for each field. VPTS CSV files that have unexpected characters in it (e.g. minus infinity coded as -Infinity instead of -Inf) can get parsed with a character type instead of a numeric type. We will want to make sure each field part of the the VPTS CSV data format standard returns the expected type