Added 'UseIsOperatorIssue'.
Added 'RewriteIfReturnToReturnIssue'.
Added 'ConvertIfStatementToConditionalTernaryExpressionIssue'.
Added 'ConvertIfStatementToNullCoalescingExpressionIssue'.
Merge branch 'master' of git://github.com/icsharpcode/NRefactory into luiscubal-while-to-do-while