generate parameters as constexprs

[emrebayrm]

parameters defined in addrmap are now generated,
In an rdl like below

addrmap atxmega #(
    longint unsigned VER_MAJOR = 0,
    longint unsigned VER_MINOR = 1,

    longint SOME_MINUS_CONSTANT = -10000000, // This is a problem, those are converted to 2's complement unsigned ints by the rdlcompiler, and they are not represented correctly.
    longint SOME_CONSTANT = 1234
) {
....
}

this is generated as below

namespace atxmega_nm
{
    constexpr uint32_t VER_MAJOR = 0;
    constexpr uint32_t VER_MINOR = 1;
    constexpr uint32_t SOME_MINUS_CONSTANT = 18446744073699551616;
    constexpr uint32_t SOME_CONSTANT = 1234;

....