Program component for splash page

Added ->
featured attribute(boolean) to person model, for checking of keynote speaker.This can adjusted by going to admin/person/edit for the particular person.

description attribute to conference(as required) to have description available for program component in splash page.

Made description attribute for tracks(as required) to show description for tracks in spalsh page.
Conditonal presence of these in the program component
Here is a snap of one such splash page with program component

![screenshot from 2014-05-21 15 47 14](https://cloud.githubusercontent.com/assets/3149236/3038701/3246d984-e0d1-11e3-8bd1-3e44f255a0d9.png)
![screenshot from 2014-05-21 15 47 24](https://cloud.githubusercontent.com/assets/3149236/3038700/324620ca-e0d1-11e3-8885-beaf9b384f45.png)