Move babel-standalone into main Babel repo (#6029)

* Move babel-standalone into main Babel repo

* Don't try to gather coverage data for babel-standalone test

* Fix JSX test

* Always use npm v4 on Travis

* Include pull request number as part of version number

* Cherry-picking 5721b2e43e

Remove deprecated packages to prevent Babel v6 files from being pulled in

* Use RootMostResolvePlugin to dedupe packages

* Avoid destructuring so the build works on archaic Node.js versions

* - Fix version number
- Remove Babili packages (they should be in separate babili-standalone)
- Remove deprecated  syntax-class-constructor-call

* - Remove more Babili packages
- Remove `babel-plugin-inline-replace-variables` for now as it pulls in Babel 6 stuff

* Actually remove reference to babel-plugin-undeclared-variables-check

* Add Babylon to root package.json so we hoist the right version. This fixes the tests.

Gulpfile.js

@@ -9,6 +9,7 @@ const watch = require("gulp-watch");
 const gutil = require("gulp-util");
 const gulp = require("gulp");
 const path = require("path");
+const registerBabelStandaloneTasks = require("./packages/babel-standalone/src/gulpTasks");
 
 const base = path.join(__dirname, "packages");
 const scripts = "./packages/*/src/**/*.js";
@@ -59,3 +60,5 @@ gulp.task("watch", ["build"], function() {
     gulp.start("build");
   });
 });
+
+registerBabelStandaloneTasks(gulp);