made the internal _Reasons an enum, since we already depend on enum34

fixes #854
Let people who are curious know how os.urandom is implemented
Attempt to link to the os.urandom docs from upstream
Merge pull request #1558 from alex/full-details2

Let people who are curious know how os.urandom is implemented
Merge pull request #1554 from alex/reasons-enum

made the internal _Reasons an enum, since we already depend on enum34
Fixed #1555 and fixed #1556 -- moved the RSA padding docs into the primary RSA doc, and tell people that PKCS1v15 isn't great
Anywhere we tell someone to randomly generate something, link the RNG docs. Fixes #1559
Merge pull request #1560 from alex/padding-move-docs

Fixed #1555 and fixed #1556 -- moved the RSA padding docs into the primary RSA doc, and tell people that PKCS1v15 isn't great
Spruced up teh RSA docs. Contains a bit more prose and hopefully helps people make better life decisions
SPelling
Merge pull request #1561 from alex/link-random

Anywhere we tell someone to randomly generate something, link the RNG docs. Fixes #1559
Fixed reST mistake
Merge pull request #1562 from alex/spruce-it-up

Spruced up teh RSA docs. Contains a bit more prose and hopefully helps people make better life decisions
Describe key generation and key loading in the RSA docs
Missing char
Merge pull request #1563 from alex/serialized-rsa

Describe key generation and key loading in the RSA docs
Provide background on asymmetric crypto in index
Merge pull request #1565 from alex/flesh-out-asymmetric-index

Provide background on asymmetric crypto in index
Reduce duplication in the serialization tests -- refs #1564
Merge pull request #1566 from alex/reduce-duplication

Reduce duplication in the serialization tests -- refs #1564