Dear buildroot maintainer:

 Since more and more traditional companies are starting using buildroot 
 with AT91SAMx chipset as their product firmware, much of them are still 
 using SVN as their version control system. So add svn repository method 
 to AT91bootstrap3 package.

It's a milestone to me that i from a parasite to a buildroot contributor, if 
there is any incorrect in this patch, feel free to tell me via email(xiangyu.chen@aol.com).

Thanks!


Br,
Xiangyu