DEV: Refactor underlyings
DEV: Add GetSmile function
DEV: Continue doc on SLV
DEV: Fix mutable since variable is declared as pointer
DEV: First definition of StochVol process for SLV implementation
DEV: Implementation of abstract class
DEV: Fix R script for regression
DEV: Add rates underlying class definition in SLV
DEV: Add Dummy Underlying in SLV
DEV: Continue doc in SLV
DEV: fix bug in SchobelZhu
DEV: continue doc on SLV