This is supposed to fix the FTP upload issue according to
travis-ci/travis-ci#9391.

- Uniform code style.

- Fixes #16271. What was appeneded was a pointer to
an object that changes during the iteration.
- The topic is allocated as a 4-byte array, fill partial topics
with 0s. Partial topics are currently disabled, but would
crash as they rely on the presence of byte number 3.

core/vm: Fixed typos in core/vm/interpreter.go

core/vm: Fixed typos

* cmd/puppeth: add constraints to network name

* cmd/puppeth: update usage of network arg

* cmd/puppeth: avoid package dependency on utils

cmd: implement preimage dump and import cmds

The parameter `rand` is unused in `PrivateKey.Decrypt`. Decryption in
the ECIES encryption scheme is deterministic, so randomness isn't
needed.

core: minor evm polishes and optimizations

Fix issue unmarshaling single parameter events from abigen generated go code #16208

* build: add GOBIN to PATH for gomobile

* build: install gobind alongside gomobile

* crypto/bn256: full switchover to cloudflare's code

* crypto/bn256: only use cloudflare for optimized architectures

* crypto/bn256: upstream fallback for non-optimized code

* .travis, build: drop support for Go 1.8 (need type aliases)

* crypto/bn256/cloudflare: enable curve mul lattice optimization

accounts/abi, core: add AddTxWithChain in BlockGen for simulation

containers: drop vagrant support, noone's maintaining it