* travis: exclude non-test jobs for PRs

We don't usually look at these builders and not starting them
removes ~15min of build time.

* build: don't run vet before tests

Recent versions of Go run vet during 'go test' and we have
a dedicated lint job.

* build: use -timeout 5m for tests

Tests sometimes hang on Travis. CI runs are aborted after 10min with no
output. Adding the timeout means we get to see the stack trace for
timeouts.

This fixes the tests on 32bit platforms.

This is a stopgap until new tests have been generated and imported.

* core/vm : fix failing testcase

* core/vm: fix nitpick

eth/downloader: fix invalid hash chain error due to head mini reorg

* core/vm: create2 address generation tests

* core/vm: per byte cost of CREATE2

* core/vm: fix linter issue in test

params: add ropsten fork delay, update les checkpoints

* core/vm/runtim: benchmark create/create2

* core/vm: do less hashing in CREATE2

* core/vm: avoid storing jumpdest analysis for initcode

* core/vm: avoid unneccesary lookups, remove unused fields

* core/vm: go formatting tests

* core/vm: save jumpdest analysis locally

* core/vm: use common.Hash instead of nil, fix review comments

* core/vm: removed type destinations

* core/vm: correct check for empty hash

* eth: more elegant api_tracer

* core/vm: address review concerns

Enable constantinople on Ropsten testnet

* cmd/puppeth: fix node URL in health check

* cmd/puppeth: set external IP for geth

* cmd/puppeth: fix enode cast issue

swarm/storage/feeds: Renamed MRU to Swarm Feeds