Further RNPM integration

Summary:
This commit removes `rnpm` folder that we left during initial merge to keep the diff cleaner. The `core`, `link` and `install` have now the same directory structure as any other command to make development more natural for all of us.

From most notable differences:
1) the `src` folder is now gone. The new structure should make it easier for people to work with the stuff and also move us closer to 100% rnpm integration,
2) There's also no `package.json` present in any of the `rnpm` packages, since they are no longer standalone modules,
3) There's no `bugs.url` in link.js since main package.json of React doesn't specify it. Decided to hardcode it to facebook/react-native since it's really unlikely to change. If one would prefer to use pkg.bugs.url as before, a separate PR modifying package.json should be sent.
Closes https://github.com/facebook/react-native/pull/9509

Differential Revision: D3751115

fbshipit-source-id: 74ae8330f7634df0887ad676808f47eee4b8de85

local-cli/link/__tests__/android/makeBuildPatch.spec.js

@@ -0,0 +1,18 @@
+'use strict';
+
+jest.autoMockOff();
+
+const makeBuildPatch = require('../../android/patches/makeBuildPatch');
+const name = 'test';
+
+describe('makeBuildPatch', () => {
+  it('should build a patch function', () => {
+    expect(Object.prototype.toString(makeBuildPatch(name)))
+      .toBe('[object Object]');
+  });
+
+  it('should make a correct patch', () => {
+    const {patch} = makeBuildPatch(name);
+    expect(patch).toBe(`    compile project(':${name}')\n`);
+  });
+});