* les: implement request distributor, fix blocking issues
* core: moved header validation before chain mutex lock

build: require Go >= 1.7

We don't use the opencl build tag anymore.

We have decided to bump the requirement to Go 1.7 because it enables
subtests and allows dropping backwards-compatibility code. This is in
line with Go's support policy. Go 1.6 and earlier no longer receive
security updates.

core/types: use gencodec for JSON marshaling code

travis: switch to cocoapods 1.2.0 stable

ethstats: try both ws:// and wss:// if none specified

Fixes #3762.  Details about parameter:
https://github.com/rs/cors/blob/a62a804a8a009876ca59105f7899938a1349f4b3/cors.go#L50-L54

light: added new CHT

* main,import: Add --nocompaction flag + multiple import files

* geth/import: documentation

* import: Added more info to err message

* fix :P

mobile: Fix typo ( Ethereun -> Ethereum )

all: update light logs (and a few others) to the new model

core: reorg logs crashed, add a check for corner cases

build: fix xgo argument order when building from make

build: bundle the bootnode too into alltools