swarm/api: integrate tags to count chunks being split and stored
swarm/api/http: integrate tags in middleware for HTTP `POST` calls and assert chunks being calculated and counted correctly
swarm: remove deprecated and unused code, add swarm hash to DoneSplit signature, remove calls to the api client from the http package
This change imports the Swarm protocol codebase. Compared to the 'swarm'
branch, a few mostly cosmetic changes had to be made:
* The various redundant log message prefixes are gone.
* All files now have LGPLv3 license headers.
* Minor code changes were needed to please go vet and make the tests
pass on Windows.
* Further changes were required to adapt to the go-ethereum develop
branch and its new Go APIs.
Some code has not (yet) been brought over:
* swarm/cmd/bzzhash: will reappear as cmd/bzzhash later
* swarm/cmd/bzzup.sh: will be reimplemented in cmd/bzzup
* swarm/cmd/makegenesis: will reappear somehow
* swarm/examples/album: will move to a separate repository
* swarm/examples/filemanager: ditto
* swarm/examples/files: will not be merged
* swarm/test/*: will not be merged
* swarm/services/swear: will reappear as contracts/swear when needed
