Add number mutators to readme
Add number mutators to readme

MakiCode/humbug,torreytsui/humbug,MakiCode/humbug,humbug/humbug,JSchwehn/humbug,oswaldderiemaecker/humbug,padraic/humbug,stof/humbug,daniel-mueller/humbug,mleko/humbug,eniuz/humbug,padraic/humbug,humbug/humbug,oswaldderiemaecker/humbug,mleko/humbug,eniuz/humbug,torreytsui/humbug,JSchwehn/humbug,daniel-mueller/humbug