CakeTime: fixed wrong daysAsSql behavior

When using the daysAsSql behavior, I would expect, that the input begin and end date are seen as days for the sql statement and NOT the generated begin and end dates.

**Example:**

User selects a date-range in the UI via local datepicker (html5 datetime input). Now (s)he would expect to receive all records for the given day (let's think of 2014-03-17 to 2014-03-18 as selected range).

**Assumptions:**

* All internal values are stored based on Europe/Vienna timezone.
* User's timezone is America/Sao_Paulo (-4h compared to Europe/Vienna)


**Code-change described in words:**
* The old implementation would return 2014-03-16 00:00:00 to 2014-03-17 23:59:59. 
* The new implementation returns, for example, 2014-03-16 20:00:00 to 2014-03-17 19:59:59.


The new implementation now returns all records for 2014-03-17 to 2014-03-18 (for the given timezone of the user).