Add transakcio set type definition, add set loading, move transakcio to
package, adapt branch to last master updates (fix compile due new common
types & git conflicts).
Update tests to pass the test, pending to adapt to new Transakcio
interface.

Change endianness to BigEndian (ಥ﹏ಥ), spec has been updated to achieve
compatibility with js & smart contracts & circuits implementations.

The coordinator implementation has been refactored to allow all the goroutines
to be handled from the node.