Add .all() method to get all occurrences of matching dates within a range.

This feature allows you to specify a start date, end date and rules, then get all
dates that match falling within that range. Accepts format as it's only parameter.

```js
var recurrence = moment().recur("01/01/2014", "01/07/2014").every(2).days();

// Outputs: ["01/01/2014", "01/03/2014", "01/05/2014", "01/07/2014"]
allDates = recurrence.all("L");
```
Add error when trying to generate dates with an start time later than the end time.
Fix bug where all dates generation was matching dates outside start/end boundaries
Merge pull request #2 from 790/enddategeneration

Add .all() method to get all occurrences of matching dates within a rang...