Repotted network stuff.
Repotted Common.h.
Document FixedHash.
Documentation for Instruction.h.
Various headers from the repotting.
Log has documentation.
Move additional Trie implementations to tests where they belong.
Clobbered a change to FixedHash? Sorry if I did - please reapply.
Merge branch 'develop' of github.com:ethereum/cpp-ethereum into develop

Conflicts:
	libethereum/Common.h