fix part 1 of issue#8 ('Namespace' object has no attribute 'PITCHFORK')

```opts``` doesn't have ```PITCHFORK``` defined, it's just a global variable.

key subdirs are only created if basedir doesn't exist (if working with -b).

The bug fixed with commit ab0e0e4 has not been reported yet. This is how it looked like before:

```
$ echo hallo|pbp -c -o hallo.pbp
1/2  Passphrase:
2/2  Repeat passphrase:
% ­¶Ì¤ÅYÍîíë>«~4xú%Ô­ÕËK"lR s5ù
```

```encrypt_handler``` used STDOUT as outfile if no infile have been specified while ignoring whatever specified with -o.