Removed an unused import.
Forgot to explicitly note python 2.5 drop in changelog for py3
Switched hash functions from PyCrypto to hashlib.

There's a few advantages to this:

1) It's probably fast, OpenSSL, which typically backs hashlib, receives far
   more attention for optimizaitons than PyCrypto.
2) It's the first step to supporting PyPy, where PyCrypto doesn't run.
Remove unused function
Switch from using PyCrypto's Random to using os.urandom.

There's several reasons for this change:

1) It's faster for reads up to 1024 bytes (nearly 10x faster for 16 byte reads)
2) It receives considerably more security review since it's in the kernel.
3) It's yet another step towards running on PyPy.
4) Using userspace CSPRNGs is considered something of an anti-pattern. See:
   http://sockpuppet.org/blog/2014/02/25/safely-generate-random-numbers/
   http://webcache.googleusercontent.com/search?q=cache:2nTvpCgKZXIJ:www.2uo.de/myths-about-urandom/+&cd=3&hl=en&ct=clnk&gl=us
The ecdsa module already defaults to using urandom.
Link back to WWW in docs sidebar
Merge branch '1.13'
Merge branch '1.12' into 1.13
Merge branch '1.10' into 1.11
Merge branch '1.11' into 1.12
Use deterministic signatures for ECDSA keys.

This is now considered the preffered approach across the board for ECDSA. This
is because with the traditional, random "k" parameter for ECDSA, any entropy
problems at all, even a single bit, about "k", results in a complete compromise
(see https://en.wikipedia.org/wiki/ECDSA#Security). The deterministic algorithm
doesn't have this downside.
Minor site cleanup
Merge branch '1.13'
Merge branch '1.12' into 1.13
Merge branch '1.10' into 1.11
Merge branch '1.11' into 1.12
Fix broken tag-tree links in changelog
This setting no longer needed & causes warnings if left in
Merge branch '1.13'