Added implementation of 'dir'

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Make the modules.py test succeed

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Additional improvements to the dir implementation

- Added dir0 which would in theory return the local scope, but
  for just returns the content of the builtins module
- Added a unit test file for dir which won't print anything as the
  list sorting does not work as expected at the moment
  (missing full implementation) and the attributes are different
  as well (pyston has some CPython 2.7.5 does not have and vice versa)
- dir1 implements the lookup on a passed object
  - If the object has a __dir__ method, it will call it and return the result
    returned by this method
  - Otherwise all class and instance attributes and methods are returned
  - If the object has a __dict__ attribute, additional to the previous one
    it will return the keys from that one as well

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Applied make format

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Extended test, usage of callattrInternal and getattr_internal

Signed-off-by: Vinzenz Feenstra <evilissimo@gmail.com>
Merge pull request #64 from vinzenz/dir-builtin

Added implementation of 'dir'