Addressing GH Dependabot npm security warnings (go-spatial#760)

Updated internal viewer bindata

Updating READMEs around ST_AsMVT

[bug] minor fix: no V directive in fmt.Printf

Vendored go-bindata build tool

Introduced the tools/ directory to allow for vendoring
tools which are not referenced elsewhere in the codebase but
necessary for development.

adjusting GH actions release event

Migrate release building to Github Actions

* Added windows build on an actual windows runner (no more xgo).
* Added linux and MacOS builds.
* Added tegola_lambda build.
* Added Docker build.
* All builds now leverage CGO as that's the path forward for now.
* Refactored Dockerfile including upgrading base images to Go
1.4.1.
* Removed .travis.yml file.
* Purged old ci scripts.
* Added release conditionals to GH Action workflow.
* Updated proto file to indicate syntax version so go generate
can be run at the repo root.