[PD-111] Made number of jobs per email configurable. 

Didn't mess with saved searches created through the API (microsites). Does affect partner saved searches and regular saved searches.
Feel free to suggest a better column name. 

![2014-10-29-155509_657x505_scrot](https://cloud.githubusercontent.com/assets/93686/4833526/6bd00fba-5fa5-11e4-94ae-95e533aedc4b.png)
![2014-10-29-155614_974x904_scrot](https://cloud.githubusercontent.com/assets/93686/4833552/9ff3640e-5fa5-11e4-97d9-8e89bbe13878.png)

PositiveSmallIntegerField is something on the order of 32k.