links audit - many dead, non-clickable, absolute

[gerbrent]

Did a little audit of links, finding that some were:

• dead -> got archive.org references
• non-clickable -> created markdown versions
  • needs testing for proper formatting to see if modifications were correct...
• absolute -> relative
  • these links lead the reader to the actual github blobs, instead of staying in the pretty website view. Links need testing to make sure mods were correct...

Note: changes made to /bonus/* need to be replicated to identical (?) content at /meditation/* - two sources of truth?

Hope this is helpful... none of the changes were tested, but they were carefully considered.

Thanks for the great read otherwise!