Added empty NoSwitchCaseFallThroughWalker
Added visitSwitchStatement as a starting point
Implemented SwitchCaseFallThroughRule.
Added test for switch fall through
Move code to visitSwitchStatement so it works with nested switches
Also added a valid case
Remove console.log from test.
Fixed line length issue
addressed feedback
Merge pull request #164 from DickvdBrink/switchCaseFallThrough

Switch case fall through