Add the configuration option to show a full stack trace

I want to add the ability to configure jasmine to show the full stack trace when running with phantomjs in the console. The short, 7 line, stack trace is not long enough to show information from files in your code. It only contains stack information from the jasmine framework.

Here is a basic example:
```javascript
it('shows a stack trace', function() {
  var foo = true;
  var bar = false;

  expect(foo).toEqual(bar);
});
```
Console output:
```
jasmine server started.
F
          Jasmine__TopLevel__Suite shows a stack trace

          Expected true to equal false.
          Error: Expected true to equal false.
    at stack (http://localhost:8887/__jasmine__/jasmine.js:1439)
    at buildExpectationResult (http://localhost:8887/__jasmine__/jasmine.js:1416)
    at http://localhost:8887/__jasmine__/jasmine.js:533
    at http://localhost:8887/__jasmine__/jasmine.js:293
    at addExpectationResult (http://localhost:8887/__jasmine__/jasmine.js:477)
    at http://localhost:8887/__jasmine__/jasmine.js:1375
1 spec, 1 failure
```