New: Run custom builds from associated commands

[stramel]

• CHANGELOG.md has been updated

Wanted to get an okay before getting too far. What I have currently functions as expected.

@FredKSchott had brought up a while ago that it would be nice for someone to add an NPM script and be able to run that from the associated Polymer CLI command. For example,

package.json

{
  "scripts": {
    "polymer:build": "gulp build"
  }
}

Then running polymer build in the console would result in the custom gulp build command being run instead of the default build process. If that NPM script is not present, it will run the default process.

I have set it up to where all commands except help follow the syntax polymer:<command>.

[kito99]

I'd like to see the ability to bypass this if necessary. For example, I'd like for polymer build to be equivalent to this: tsc && polymer build. As-is, this would cause an infinite loop, so we'd need support for something like this: tsc && polymer build -bypass-custom-commands.

[stramel]

@kito99 Ah, I see what you mean. I think we could easily add a --bypass-custom-command, --ignore-custom-command, or whatever naming the Polymer team would want for a flag to bypass.

[stramel]

Ping @justinfagnani I can't remember what you wanted done here.