Rolls a 20-sided die.
The number of dice to roll. (Default: 1)
Returns the total from rolling nNumDice x d20 dice.
If nNumDice is less than 1, then 1 is used.
A d20 (twenty sided die) has a 5% probability of turning up any one number.
nNumDice has a limit of 255 (BYTE == uin8_t == 0-255).
author: Charles Feduke