Use vfsgen to statically embed template data.

[dmitshur]

• Remove deprecated Makefile build process.
• Replace use of go-bindata with vfsgen for embedding template data. As a side effect, this removes the need to gofmt the generated output.
• Move go generate directives into ./traceapp/tmpl package, since that's the only package they affect.

  Rationale

Reasons for switching to vfsgen include:

• Consistency across all Sourcegraph code bases.
  • Other projects need vfsgen for its additional functionality, and it's good to use the same tool for this task.
• Ability to easily enable gzipped compression efficiently in the future.
• No need for a follow-up go fmt ./... after regeneration.
• Usage of http.FileSystem directly matches the needs of this project (bonus of being done in one package instead of across two separately maintained packages).

[dmitshur]

I've tried to keep the filenames unchanged to make it easier to review.

traceapp/tmpl/data_src.go is still the // +build dev live disk reload version, but it's a much smaller file now because it simply uses http.Dir. It defines an Assets var, and that's what's used in dev mode, as well as by vfsgen during go generate to generate data.go file.

traceapp/tmpl/data.go is still the // +build !dev go generated static embedded version, but it's now generated with vfsgen.

[dmitshur]

Travis CI is failing, but not sure if that's related to my changes or external. The last master build was successful, but it was 12 days ago. Can someone with access restart CI to check if master is still passing?

[dmitshur]

It turns out Travis is passing on master even now, so this appears to be a legitimate failure due to my changes in this PR. I'll try to see what the cause could be.

[slimsag]

@shurcooL I suspect perhaps the filepaths have changed somehow, but can't say for certain

[slimsag]

On second thought, this appears unrelated to your change. Running master locally (go test -v ./...) produces the same test failures for me.

[dmitshur]

The Makefile that was in the root folder previous to being removed in this PR was causing Travis not to run tests at all, that's why it succeeded.

See the bottom of https://travis-ci.org/sourcegraph/appdash/jobs/79379987 output:

The command "make" exited with 0.

Done. Your build exited with 0.

[slimsag]

@shurcooL I've merged #85 in, please rebase so we can see whether or not that fixed the issue :)

[dmitshur]

Done, and it's green now.

[slimsag]

LGTM