Add preview on hover for slide teaser and links view modes.

#5393 

Added hover preview for the "slide teaser" and "links" view modes:
![selection_033](https://f.cloud.github.com/assets/4497748/2521981/03b50178-b4b6-11e3-9b2e-29296052566b.png)
![selection_035](https://f.cloud.github.com/assets/4497748/2521992/45baf852-b4b6-11e3-9d4e-bf30ad3a4847.png)