BUG: class static member scope

[Andrei-Pozolotin]

1. in python and brython the following works fine:
   https://www.brython.info/tests/editor.html?lang=en

class DataUnit:
 static_one = 'one'
 static_two = 'two'
 static_total = static_one + static_two

2. in transcrypt, generated js uses direct mapping

...
{
 static_one : 'one',
 static_two : 'two',
 static_total : static_one + static_two // SCOPE NOT AVAILABLE
}

3. solution: generated js could use class prefix:

...
{
 static_one : 'one',
 static_two : 'two',
 static_total : DataUnit.static_one + DataUnit.static_two,
}

[Andrei-Pozolotin]

additional problem with static scope: it is not executed

class DataUnit:
 print('this is not printed')

[AlexECX]

Could be merged with #630. Also note that when the initializer object is used to create the class, DataUnit does not exist yet.