Initial commit
Merge remote-tracking branch 'orig/master'

Conflicts:
	README.md
Big int support.
Repotting.
Tests.
Docs.
Add SHA-256 implementation.
Added Virtual Machine stub.
Half-implenentation of RLP encoder and Merkle tree hasher.
Hex-prefix Notation for the Merkle tree.
All tests passed for 2-way RLP.
Merkle hash implementation. Needs testing.
Virtual machine and switch to Boost's big num type for 256-bit ints.
Removed unneeded int classes.
merkle tree hash works.
Full Trie I/O implementation with tests and cross-checker with
alternative implementation.
Code cleanups.
Reorganised source directory.
Codebase cleanups - renaming files.
RIP-EMD160 implementation for the VM.
Additional VM instructions.
VM nearly instruction-complete.
More VM implementation stuff.