iPad support for Three20 framework

by Chih-Wei Lee for Facebook

This proposal is intended to add iPad support to current three20 framework and make three20 full compatible with iPad. The contributor is going to take three steps to accomplish the goal. The first goal is to clean the dirty codes on Three20 project. The second goal is to add more iPad support to Three20 frameworks. The third goal is to modify the current Three20 sample applications to become universal ones.