Allow integer values in `select` and `radio` Components

[howeaj]

A typical way you would want to represent a list of options in C would be as an enum, i.e. integers.

The select and radio components only allowing string values makes this a pain.

Ideally, you should be able to specify integer values in the config.json and it Just Work, but currently ints get silently converted to strings so that would be a breaking change. Alternatively there could be an extra Property valueType or whatever.

[howeaj]

As a workaround in the meantime: if you don't need a value bigger than 9, you can just specify the values as strings "0", "1", "2" etc and convert them to integers on the C side with tuple->value->int32 - '0'.
If you need a number bigger than 9 then strtol() I guess, or just continue into the rest of the character set.
Another option might be to specify bytes in the json with "\u0000", "\u0100" etc.