add license and donate link to readme.txt

readme.txt

@@ -4,6 +4,10 @@ Tags: facebook, wordpress.com, twitter, google, yahoo, social, login, register
 Requires at least: 3.0
 Tested up to: 3.8
 Stable tag: 0.10.3
+License: GPLv2
+License URI: http://www.gnu.org/licenses/gpl-2.0.html
+Donate link: https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=EG7NAXM8ES42E&lc=BR&item_name=Social%20Connect%20Plugin&item_number=social%2dconnect&currency_code=BRL&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted
+
 
 Allow your visitors to comment, login and register with their Twitter, Facebook, Google, Yahoo or WordPress.com account.