cmd/swarm: Exit if --ethapi is set

The previous attempt to use --ethapi as a fallback if --ens-api is not
set does not work because --ens-api has a default value, and also
setting --ens-api to "" is the suggested way to disable ENS lookups.
Signed-off-by: Lewis Marshall <lewis@lmars.net>

cmd/swarm: Support using Mainnet for resolving ENS names

Fix error when reporting numer of txs in imported blocks

core/vm: fix overflow in gas calculation formula

With this commit, core/state's access to the underlying key/value database is
mediated through an interface. Database errors are tracked in StateDB and
returned by CommitTo or the new Error method.

Motivation for this change: We can remove the light client's duplicated copy of
core/state. The light client now supports node iteration, so tracing and storage
enumeration can work with the light client (not implemented in this commit).

common/hexutil: wrap errors in json.UnmarshalTypeError

This adds type and struct field context to error messages.
Instead of "hex string of odd length" users will now see "json: cannot
unmarshal hex string of odd length into Go struct field SendTxArgs.from
of type common.Address".

* accounts/abi: reorganizing package and some notes and a quick correction of name.
Signed-off-by: RJ Catalano <rj@monax.io>

get rid of some imports
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: move file names
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fix boolean decode function
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fix for the array set and for creating a bool
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: be very very very correct
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fix up error message and variable names
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: take out unnecessary argument in pack method
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: add bool unpack test and add a panic to readBool function
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fix panic message
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: change from panic to basic error
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fix nil to false
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fill out type regex tests and fill with the correct type for integers
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: move packNumbers into pack.go.
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: separation of the testing suite into appropriately named files.
Signed-off-by: RJ Catalano <rj@monax.io>

* account/abi: change to hex string tests.
Signed-off-by: RJ Catalano <rj@monax.io>

* account/abi: fix up rest of tests to hex
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: declare bool at the package level
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: use errors package in the error file.
Signed-off-by: RJ Catalano <rj@monax.io>

* accounts/abi: fix ugly hack and fix error type declaration.
Signed-off-by: RJ Catalano <rj@monax.io>

cmd/puppeth: fix key reuse during faucet deploys

Signed-off-by: Lewis Marshall <lewis@lmars.net>

whisperv5: integrate whisper and implement API

core: remove unused events

Demo of the issue: https://play.golang.org/p/EeTLFfppqC

swarm/storage: remove panic on invalid chunk

* Makefile: add make swarm command

* Makefile: minor code formatting polishes

README: change heading to "Go Ethereum"

consensus/clique: choose valid votes

eth: gracefully error if database cannot be opened

travis.yml, cmd/swarm: fix Travis CI build