Fixed Twitter and Github social links in profiles.

Fixed social profile links, the twitter and github link were being created with the username and not the social account username.

__Github link error__
![horas_github_link_bug](https://cloud.githubusercontent.com/assets/1918027/2954570/91237dee-da74-11e3-832a-f04065e1a20a.png)

__Github link fixed__
![horas_github_link_fixed](https://cloud.githubusercontent.com/assets/1918027/2954687/7a02b650-da76-11e3-9cfd-9164328baed7.png)

__Twitter link error__
![horas_twitter_link_bug](https://cloud.githubusercontent.com/assets/1918027/2954606/405b0e62-da75-11e3-9b80-e56458007d05.png)

__Twitter link fixed__
![horas_twitter_link_fixed](https://cloud.githubusercontent.com/assets/1918027/2954692/8dc63b6c-da76-11e3-9ba8-65c81316152f.png)

Added some instructions to handle missing libmemcached lib for Mac OS X to the README.md
Added some more entries to the .gitignore fils