Add Rsync Exclude File

Hi Dan,

thanks for this great application. I really love it!
What do you think about adding an exclude file for rsync? The c5 docs recommend not to copy /files/tmp and /files/cache : http://www.concrete5.org/documentation/installation/moving_a_site/ . So this saves some time and should also prevent errors.
I'm not sure though if I implemented it the way you had in mind. 

Best
Patrick

PS: I also made two minor changes to make the script compatible with PHP 5.2