Pull request for issue: #208

This is a pull request for the following functionalities:

How to test?

Visit the home page and verify the following:

I expect there are no news items to display, so the section should not be displayed at all
go to protected/components/NewsAndFeedsService.php and in the getTodaysNews function remove the second conditional so that all news are displayed
refresh the home page. you should see a news section with a carousel and news boxes
clicking on a "read more" link should open the detail page

alternatively you can create more news items from the admin page http://gigadb.gigasciencejournal.com/news/admin and they should show up in the home page

the carousel uses the bootstrap carousel and overrides the styles to match the gigadb colors and to make it look better
the logic was tweaked to cover a handful of use cases:
- the carousel is responsive and reactive to the screen width
- mobile shows one item
- medium screen shows two items
- desktop shows three items
- if the number of items to display is less than the maximum, for example, for desktop, if there are just two news items, rather than showing a blank space, the two news items fill all the space
- if there are less news items than the maximum that can be displayed at any given time (e.g. 3 for desktop) then the carousel controls are hidden

tests pass. As far as I have seen, there are no acceptance tests covering this case