Set declarationMap true

Hi, first of all thanks for the great library. It has speeded up my learning curve greatly. I am a new Angular developer and I would like to see source codes of some modules such as Auth. Instead there is only `d.ts` files which are only including declarations. I have checked that adding `declarationMap` into Typescript configuration results in creating source maps to easy access source codes. Would you please add `declarationMap` in configuration?