Function execute_charstring_mm 

pub fn execute_charstring_mm(
    charstring: &[u8],
    subrs: &[Vec<u8>],
    len_iv: usize,
    width_only: bool,
    cs_lookup: Option<&dyn Fn(&str) -> Option<Vec<u8>>>,
    weight_vector: Option<&[f64]>,
) -> Result<CharstringResult, String>

Execute a Type 1 charstring with Multiple Master weight vector support.