vendor: update vendored packages (#791)

* pkg/proc: use golang.org/x/arch/x86/x86asm

instead of rsc.io/x86/x86asm

* pkg/dwarf: migrate to github.com/pkg/profile

from github.com/davecheney/profile

* scripts: keep script go files from being considered for the build

scripts/gen-*.go files are scripts for generating documentation
files and don't follow the typical Go package layout. Expected
usage is like

   go run scripts/gen-cli-docs.go

* vendor: update vendored packages

There were many changes in delve, and go tool chains since last
vendored package update. I just rerun godpes from scratch.

$ rm vendor/*
$ rm Godeps/Godeps.json
$ go list ./... | grep -v /vendor/ | grep -v /scripts/ | go get -u -t
$ go get -u github.com/mattn/go-colorable
$ go get -u github.com/mattn/go-isatty
$ go list ./... | grep -v /vendor/ | grep -v /scripts/ | godeps save

scripts/gen-usage-docs.go

@@ -1,3 +1,5 @@
+// +build ignore
+
 package main
 
 import (