- add 2013 where there was only 2012
Notable omissions from updates:
- contrib/bitcoind.bash-completion -- no copyright by The Bitcoin developers
- contrib/testgen/gen_base58_test_vectors.py -- no copyright by The Bitcoin developers
- src/addrman.cpp -- no copyright by The Bitcoin developers
- src/addrman.h -- no copyright by The Bitcoin developers
- src/leveldb/* -- I figure this can be updated by pulling in upstream code
Fixes #2217.