Missing floating-point `Kapacity` operator support.

[DeveloprOfThings]

The library should offer operation overloads for floating-point data times ie Double and Float, similar to what's available for Integral types. Something along the following lines:

operator fun plus(bytes: Double): Kapacity
operator fun plus(bytes: Float): Kapacity
operator fun minus(bytes: Double): Kapacity
operator fun minusbytes: Float): Kapacity
operator fun times(bytes: Double): Kapacity
operator fun times: Float): Kapacity
operator fun div(bytes: Double): Kapacity
operator fun div: Float): Kapacity