Fix README whitespace and code blocks
Make Travis CI install Bower before tests

Travis CI should globally install Bower before running the tests.
Also run the tests in Node.js 0.10 as well as 0.8
Use Karma test runner; remove Grunt dependency

Remove all the Grunt dependencies and switch to using the Karma test
runner.

Setup the Karma configuration file to load all the tests and library
dependencies. It's configured to use the RequireJS and Jasmine adapters.
Unit tests will be run and watched in Chrome and Firefox when
`karma start` is run during develop. CI tests are run once in PhantomJS.

The `test-main.js` file is needed to configure RequireJS for Karma, and
filter out the tests in the list of files provided to Karma.
Rename and fix the test files

Use the `*.spec.js` naming convention for tests, which also makes it
easy to filter out the tests for Karma. Move the tests into a `spec` dir
to clearly separate them from the RequireJS test config file.

Replace use of `require()` in the test files with `define()`.
Add development notes to README
Improve Bower command in README

Get Bower to save the installation in the project's `bower.json`.
Update `.gitignore`
Merge pull request #4 from necolas/fix/test-setup

New test setup