add `default` field into `Key`

[icreator]

Please add default field into Key:

    val nameKey = Key("name", stringType, "DefaultName")
    val name = config[nameKey] /// if not contains in CONFIG -> ="DefaultName"

If use -h command it will print:

Description of NAME. Default value: DefaultName

And if not setted in configuration - use Deafult Value

instead I do now:

    val connectiontimeoutKey = Key("connection.timeout", intType)
    fun getConnectionTimeout(): Int {
        return if (connectiontimeoutKey in vals) vals[connectiontimeoutKey]
        else DEFAULT_CONNECTION_TIMEOUT
    }

but I need:

    val connectiontimeoutKey = Key("connection.timeout", intType, DEFAULT_CONNECTION_TIMEOUT)
    fun getConnectionTimeout(): Int {
        return vals[connectiontimeoutKey]
    }

[icreator]

IDEA!
instead of Key("name", stringType, "DefaultName")

use Key("name", "DefaultName")

defaultValue - has class type already