Update format arguments such that they are suitable for NSInteger/NSUInteger

[tonyarnold]

This resolves the following warnings in Xcode 6 and higher:

WTReParser.m:162:56: Values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead
WTReParser.m:167:51: Values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead
WTReParser.m:169:52: Values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead
WTReParser.m:171:66: Values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead
WTReParser.m:511:119: Values of type 'NSUInteger' should not be used as format arguments; add an explicit cast to 'unsigned long' instead