Merge pull request #458 from TheBlueMatt/copyright

Unify copyright notices.

diff --cc src/db.cpp
Simple merge

diff --cc src/key.h
Simple merge

diff --cc src/main.cpp
Simple merge

diff --cc src/net.cpp
Simple merge

diff --cc src/net.h
Simple merge

diff --cc src/script.h
Simple merge

diff --cc src/serialize.h
Simple merge