Merge pull request bitcoin#560 from kn0rhaan/patch-1

fixed small typo [in BIP 30]

Author: luke-jr

bip-0030.mediawiki

@@ -12,7 +12,7 @@
 </pre>
 
 ==Abstract==
-This document gives a specification for dealing with duplicate transactions in the block chain, in an attempt to solve certain problems the reference implementations has with them.
+This document gives a specification for dealing with duplicate transactions in the block chain, in an attempt to solve certain problems the reference implementation has with them.
 
 ==Copyright==