Replace Integer with Int in Meta files

[arnavk23]

Fixes #420
@tmigot done using

dir = "src/Meta"
for f in readdir(dir, join=true)
    if endswith(f, ".jl")
        s = read(f, String)
        s2 = replace(s, "n::Integer" => "n::Int")
        if s != s2
            println("Updating $f")
            write(f, s2)
        end
    end
end