Macros for creating compile-time EOSIO names and symbols.

Creating EOSIO names:

```rust
use eosio_numstr_macros::n;
assert_eq!(n!(test), 14_605_613_396_213_628_928);
assert_eq!(n!(1234), 614_248_767_926_829_056);
assert_eq!(n!(123451234512), 614_251_535_012_020_768);
assert_eq!(n!(eosio.token), 6_138_663_591_592_764_928);
```

Creating EOSIO symbols:

```rust
use eosio_numstr_macros::s;
assert_eq!(s!(0, TGFT), 361_956_332_544);
assert_eq!(s!(4, EOS), 1_397_703_940);
assert_eq!(s!(0, EOS), 1_397_703_936);
assert_eq!(s!(1, EDNA), 280_485_971_201);
```