Add some more examples to README

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

README.md

@@ -22,10 +22,14 @@ they are added as-needed.
 
 `${random 6}` => `4`
 
-`${choose a b c d}` => `d`
+`${random 90 100} bottles of beer on the wall` => `96 bottles of beer on the wall`
+
+`${choose heads tails}` => `heads`
 
 `${round 6.4}` => `6`
 
+`${round ${random}}` => `0`
+
 ## Available macros
 
 * `random [X [Y]]` - chooses a random number. If no arguments are supplied, chooses a random number