feat: export savingsUtils namespace (#19)

Author: alex-rie

src/calculators/index.ts

@@ -7,3 +7,4 @@ export * from './savings-end-value'
 export * from './savings-interest-rate'
 export * from './savings-payment'
 export * from './savings-start-value'
+export * as savingsUtils from './savings-utils'