Added TOTP implementation and tests.
Added documentation for TOTP.
Small fixes
Fixed documentation based on alexs' comments.
Updated secret key description
Added method definitions to TOTP documentation.
Updated HOTP and TOTP doctests
Added __future__ import statement
Fixed documentation
Fixed whitespace issue pointed out by flake8
Fixed wrong param naming in totp documentation
Seperated the totp tests based on different hash types
Merge pull request #688 from reaperhulk/fix-warning

SSL_session_reused should return a long
Merge pull request #637 from Ayrx/totp-impl

TOTP Implementation
Do some nitpicking cleanup of the twofactor code and documentation.
Add TOTP to the changelog.
Merge pull request #689 from dreid/twofactor-cleanup

Cleanup twofactor docs and code.
Re-linewrap the symmetric encryption doc source
Merge pull request #690 from alex/linewrap

Re-linewrap the symmetric encryption doc source
Cite Thomas Ptacek for urandom