Improve unreachable rule for unbraced conditionals (#83 and #31)

There should no longer be false positives for if and else statements
without braces that end in return (and similar statments) for the
no-unreachable rule.
Merge pull request #97 from gscshoyru/improve-unreachable-rule

Improve unreachable rule for unbraced conditionals (#83 and #31)