Add @openzeppelin/contracts as alternative package name (#1840)

* Rename package and repository name from docs and scripts

* undo root package rename

* add @openzeppelin/contracts as subpackage with release automation

* synchronize @openzeppelin/contracts version

* remove private field from package.json

* make file patterns absolute

* change wording of a comment

* use a saner version script

(cherry picked from commit b8c8308d77)

scripts/release/synchronize-versions.js

@@ -0,0 +1,18 @@
+#!/usr/bin/env node
+
+// Synchronizes the versions in ethpm.json and contracts/package.json with the
+// one in package.json.
+// This is run automatically when npm version is run.
+
+const fs = require('fs');
+const cp = require('child_process');
+
+setVersion('contracts/package.json');
+setVersion('ethpm.json');
+
+function setVersion(file) {
+  const json = JSON.parse(fs.readFileSync(file));
+  json.version = process.env.npm_package_version;
+  fs.writeFileSync(file, JSON.stringify(json, null, 2) + '\n');
+  cp.execFileSync('git', ['add', file]);
+}