Use RTD links in README (#468)
Use RTD links in README (#468)

Closes #467.
Dallinger/Dallinger,berkeley-cocosci/Wallace,Dallinger/Dallinger,jcpeterson/Dallinger,berkeley-cocosci/Wallace,Dallinger/Dallinger,jcpeterson/Dallinger,jcpeterson/Dallinger,suchow/Wallace,Dallinger/Dallinger,suchow/Wallace,jcpeterson/Dallinger,Dallinger/Dallinger,jcpeterson/Dallinger,berkeley-cocosci/Wallace,suchow/Wallace