Fixed up some backwards syntax in the docs
Merge pull request #534 from alex/docs-fixes

Fixed up some backwards syntax in the docs
Initial work on a prioritized multibackend for which implements CipherBackend
HashBackend is now supported by PrioritizedMultiBackend
Added support for HMAC backend
Added PBKDF2HMAC support
Replace re-running all tests with some unit tests
Direct tests for the cipher support
Direct tests for the hash support
Only make teh default once
Not true anymore
More direct tests
Fix
PKCS#1 vectors

From ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/ and
ftp://ftp.rsa.com/pub/rsalabs/tmp/
pep8 fixes
Merge pull request #537 from public/pkcs1-vectors

PKCS#1 vectors
Fixes #539 -- document which interfaces a backend implements
Complete sentences.
Merge pull request #540 from alex/document-interfaces

Fixes #539 -- document which interfaces a backend implements
Handle multiple errors on the stack