Fixed bug with loading default (console) reporter, when config.json is
not located in CWD.
Added support for running tests with chrome, in addition to phantomjs.

Updated docs to include instructioons on setting the browser.

Example:

```bash
config=config.json env=development browser=chrome portal simple_test.js
```
Merge pull request #2 from selenium-portal/dev

Bug fixes and new option to run tests in Chrome