Parser issues related to functions and blocks

* block statement parsing is wrong - accepts function end "}" for missing blocks of if, while, case statements

* function closure expressions should be assignmentExpressions

* Implicit new line at EOF is not accepted for 'return', 'yield', 'continue' and 'break'

>> [Parser code review]:
>>
>> jjs> (function(){case0:})()
>> jjs> (function(){if(0)})()
>> jjs> (function(){if(0);else})()
>> jjs> (function(){while(0)})()
>> => should throw SyntaxError exceptions
>>
>> jjs> function sq(x) x,x*x
>> function sq(x) x,x*x
>> => should be restricted to AssignmentExpression instead of Expression (to match SpiderMonkey and most likely Rhino, but haven't checked the latter)
>>
>> jjs> Function("return")
>> jjs> Function("yield")
>> jjs> Function("for(;;)continue")
>> jjs> Function("for(;;)break")
>> => should not throw SyntaxError exceptions
>>