Here are some guys like me who make a lot of experiments with the theme. And doing so, we needed to use either FTP or the control panel provided by the host to view the changes “Live”. The control panel is not always that good experience!!! And doing FTP for each small change is a very very bad idea. Isn’t it???
When I upgraded to 2.7, I found the solution of this problem. Actually thanks to wordpress guys, they provided us the ability to edit the themes files from wordpress admin panel itself. You can edit all your theme files from your appearance –> Editor option.
Then scroll dopwn and click on update: