[docs] Improving installation instructions for Ubuntu 12.04
[docs] Improving installation instructions for Ubuntu 12.04

heitortsergent/azk,marcusgadbem/azk,gullitmiranda/azk,fearenales/azk,fearenales/azk,azukiapp/azk,teodor-pripoae/azk,nuxlli/azk,azukiapp/azk,Klaudit/azk,renanmpimentel/azk,renanmpimentel/azk,Klaudit/azk,agendor/azk,agendor/azk,juniorribeiro/azk,slobo/azk,gullitmiranda/azk,teodor-pripoae/azk,marcusgadbem/azk,saitodisse/azk,heitortsergent/azk,juniorribeiro/azk,saitodisse/azk,slobo/azk,nuxlli/azk