BUG : minor tweak to getting default values
MNT/API : split wrap_lib in half

 scrape.py -> logic to scrape docstrings
 wrap_lib.py -> logic to turn output from scarpe.py into VT modules

 - modified bunch of functions to seperate logic
 - rename test_wrap_lib -> test_scrape as it was only testing scraping functions
TST : added a bit more test coverage