Update for D2L version 10.1 - No longer breaks everything

 - Still need to fix up nested directory (D2L manages with JS :screamcat:)
Learn Update 10.1 breaks everything
pt.2

 - download subdirectories on the content outline page
 - determine file extension before downloading
credits
refactored updated solution for learn document downloading
updated fix for learn not allowing certains files; weird mechanize parsing error (on pdfs only? something to do with hex values in the response)
Merge pull request #12 from asvoboda/update-10.1

Update D2D for the Learn breaking changes