Add github.ReportCrash to send user errors.
Simplify title and body hint message creation.
Generate crash report editor message.

- Check report crash option saving.
Make anonymous gh update possible
Move client init down close to use
Use stub credentials for update client
Add test to downloadFile
Pass in DefaultHost from NewUpdater
Test unzipExecutable
Fix bug that it doesn't update if timestamp is invalid
Merge pull request #162 from jingweno/anonymous_update

Should gh update require user login?
Update README to install/update from source

We lock down dependencies with Godep so `go build` won't work
Merge pull request #164 from jingweno/update_build_from_source

Update README to install/update from source
Add instruction for building gh from source
Don't use we
Explicitly build to gh
Merge branch 'master' into crash_report

* master: (70 commits)
  Explicitly build to gh
  Don't use we
  Add instruction for building gh from source
  Update README to install/update from source
  Fix bug that it doesn't update if timestamp is invalid
  Test unzipExecutable
  Pass in DefaultHost from NewUpdater
  Add test to downloadFile
  Use stub credentials for update client
  Move client init down close to use
  Make anonymous gh update possible
  Remove logs.
  Make sure we test against a good version of git.
  Import fmt.
  Log the submodule process.
  Announce step to see what travis is executing.
  Remove @wip from `submodule add`.
  Revert "Remove @wip from `submodule add`."
  Remove @wip from `submodule add`.
  Be more explicit on API error message
  ...

Conflicts:
	commands/pull_request.go
	commands/release.go
	github/editor.go
Move the crash report to the new editor.
Report error, stack and runtime information.
Add error type to the report.