Search YAJL Parser created_at entry inconsistant with other results.

[averydev]

When results for a search are parsed with YAJL, the "created_at" key is returned as an NSCF Number instead of an NSDate.

Starting at line 81 in MGTwitterYAJLParser
the following code changes that:
if ([currentKey isEqualToString:@"created_at"])
{
// we have a priori knowledge that the value for created_at is a date, not a string

    NSDateFormatter *dateformat  = [[NSDateFormatter alloc] init];
        [dateformat setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];
        dateformat.dateFormat = @"EEE, dd MMM yyyy HH:mm:ss ZZZZZ";

        NSDate *creationDate = [dateformat dateFromString:(NSString *)value];
        [self addValue:creationDate forKey:currentKey];
        [dateformat release];
    }