resets includes to work with the flattened prim structure throughout the entire stan math library

edit_includes.sh

fldrs=("rev" "mix" "fwd" "prim")

for fldr in "${fldrs[@]}";
do
    echo $fldr
    ## parsing all .hpp files in rev, mix and prim
    for f in ./stan/math/$fldr/*/*/*.hpp
    do
        echo $f
        sed -i -e "s/stan\/math\/prim\/scal/stan\/math\/prim/g" $f ## remove scal
        sed -i -e "s/stan\/math\/prim\/mat/stan\/math\/prim/g" $f  ##  "" mat
        sed -i -e "s/stan\/math\/prim\/arr/stan\/math\/prim/g" $f  ##  "" arr

        ## edit higher level includes
        sed -i -e "s/stan\/math\/prim\/scal.hpp/stan\/math\/prim.hpp/g" $f
        sed -i -e "s/stan\/math\/prim\/mat.hpp/stan\/math\/prim.hpp/g" $f
        sed -i -e "s/stan\/math\/prim\/arr.hpp/stan\/math\/prim.hpp/g" $f
        
    done
    for f in ./stan/math/rev/core/*.hpp
    do
        echo $f
        sed -i -e "s/stan\/math\/prim\/scal/stan\/math\/prim/g" $f ## remove scal
        sed -i -e "s/stan\/math\/prim\/mat/stan\/math\/prim/g" $f  ##  "" mat
        sed -i -e "s/stan\/math\/prim\/arr/stan\/math\/prim/g" $f  ##  "" arrx
    done

    ## editing the higher level includes
    for f in ./stan/math/$fldr/*.hpp
    do
        echo $f
        sed -i -e "s/stan\/math\/prim\/scal/stan\/math\/prim/g" $f
        sed -i -e "s/stan\/math\/prim\/mat/stan\/math\/prim/g" $f
        sed -i -e "s/stan\/math\/prim\/arr/stan\/math\/prim/g" $f

        ## edit higher level includes
        sed -i -e "s/stan\/math\/prim\/scal.hpp/stan\/math\/prim.hpp/g" $f
        sed -i -e "s/stan\/math\/prim\/mat.hpp/stan\/math\/prim.hpp/g" $f
        sed -i -e "s/stan\/math\/prim\/arr.hpp/stan\/math\/prim.hpp/g" $f
        
    done
done