Make Hovering over Portfolio items use  Primary Color

I noticed that after switching the primary and secondary color in the config, hovering over portfolio items was still using the original primary color:

Example now:
![screen shot 2014-11-06 at 9 53 59 am](https://cloud.githubusercontent.com/assets/4104448/4937645/2a34cdcc-65c5-11e4-8d4e-96e34fdb198c.png)

I added a small plugin that adds a filter to simply change the hex values we have in the `_config.yml` as primary color into RGB values so we can keep the alpha of 0.9 that the hover currently uses

Example after this change:
![screen shot 2014-11-06 at 9 56 05 am](https://cloud.githubusercontent.com/assets/4104448/4937687/8a24cff2-65c5-11e4-9dad-5ddfaedb3007.png)