requireSemicolon implementation

Boolean rule that requires semicolon after:
* var declaration
* expression statement
* return
* throw
* break
* continue
* do-while

Valid:
```js
var a = 1;
var fn = function(){ return; };
if (a > 0)
  b = a * 5;
```

Invalid:
```js
var a = 1
var fn = function(){ return };
if (a > 0)
  b = a * 5
```