Fix a couple of hash links in the README

Author: randycoulman

README.md

@@ -73,7 +73,7 @@ Here's a rough outline:
   1. [for Node.js](docs/1-installation.md#for-use-in-nodejs-or-browserify)
   2. [for browsers](docs/1-installation.md#for-use-in-browsers)
   3. [initial configuration](docs/1-installation.md#configuring-testdoublejs-setting-up-in-your-test-suite)
-2. [Purpose of testdouble.js](docs/2-howto-purpose.md#background)
+2. [Purpose of testdouble.js](docs/2-howto-purpose.md#purpose)
   1. [in unit tests](docs/2-howto-purpose.md#test-doubles-and-unit-tests)
   2. [in integration tests](docs/2-howto-purpose.md#test-doubles-and-integration-tests)
 3. [Getting started tutorial](docs/3-getting-started.md#getting-started)
@@ -131,5 +131,5 @@ Here's a rough outline:
   2. [testdouble-jasmine](https://github.com/BrianGenisio/testdouble-jasmine)
 11. [Frequently Asked Questions](docs/B-frequently-asked-questions.md#frequently-asked-questions)
   1. [Why doesn't `td.replace()` work with external CommonJS modules?](docs/B-frequently-asked-questions.md#why-doesnt-tdreplace-work-with-external-commonjs-modules)
-12. [Configuration](docs/C-configuration.md)
+12. [Configuration](docs/C-configuration.md#configuration)
   1. [td.config](docs/C-configuration.md#tdconfig)