Pay attention to the size OpenSSL returns.

This avoids creating an excessively padded signature and potentially
 leaking junk in memory.
Implement MurmurHash3()
Implement CBloomFilter class

Currently missing IsRelevantAndUpdate(), but that isn't very useful
unless you are a full node.
Merge pull request #8 from petertodd/cbloomfilter

Implement CBloomFilter class
Merge pull request #6 from gmaxwell/siglength

Pay attention to the size OpenSSL returns.
Python optimizations strip out asserts. Fix that.
ECDSA_verify returns 1 on success, 0 on invalid signatures, but -1 for errors, which is still bool(-1)==True.
Merge pull request #9 from sarchar/master

Small fixes to key.py
Add python3 import __future__
Change xrange to range for python3 compatibility
Make long int usage Py3 compatible

In particular Python ints are promoted to longs automatically when
needed, so trailing L's are almost never needed.
Replace iterkeys with keys for python3 compatibility
Fix broken tab using indentation

Might have broken the code, but it didn't have a unittest so I don't
care.
Make (un)hexlify() usage py3 compatible
Fix chr/ord related py3 incompatibilities
Add python3 invocation of unittests
Merge pull request #10 from petertodd/python3-fixes

Python3 fixes