A few changes to improve compatibility

There were a few places where the return type defined in the interface did not match the locally typed variable. In this pull request I changed to local variable to match the interface type or fixed places where the TabeView delegate type did not match the overriding method type.

### Example:
Apple defines  as - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath  but src/UIBubbleTableView.m had it as "float"

see: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITableViewDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intfm/UITableViewDelegate/tableView:heightForRowAtIndexPath: