Fix #1079

Restore the functionality from here:
https://github.com/kennethreitz/requests/blob/v0.14.2/requests/models.py#L884
Update the advanced doc to use the r.json method
Update the link headers doc to match the code
Clarify support for alternative distributions
Merge pull request #1089 from PaulMcMillan/philosophy

Clarify support for alternative distributions
Merge pull request #1086 from graingert/patch-2

Update the link headers doc to match the code
Merge pull request #1085 from graingert/patch-1

Update the advanced doc to use the r.json method
Merge pull request #1080 from sigmavirus24/master

Fix #1079