Minor fix in the doc

If I run the example as is I get:
```
TypeError: Cannot call method 'getTime' of undefined
```
Adds purgeLogsAfterDays parameter and example app
Merge pull request #5 from grigio/master

Minor fix to the example in the doc
Merge pull request #6 from SachaG/master

Adds getNext function
Renames getNext to nextScheduledAtDate and adds tests
Adds configuration options
Bumped version number.
Default to localtime for later.js scheduling. Bumped version to 0.2.2
Correctly sets _timer on entry
updating for 0.9