Fixed bug in UnreachableCodeIssue: Labels were incorrectly being marked as unreachable.
UnreachableCodeIssue: Don't consider blocks unreachable if they contain any statements reachable (e.g. due to a goto statement).
Merge pull request #272 from mono-soc-2013/luiscubal-fix-reachability-goto

Fix UnreachableCodeIssue for gotos