Fix an 'import *'

Interestingly Jython 2.7 (beta1) regards this as a syntax
error - although the rest of the buildbots seemed happy:

SyntaxError: 'import *' not allowed with 'from .'
Disable installation under Python 3.1 (unittest import broke)

Disabling Python 3.1 is due to the recent change to relative
imports (via the 2to3 import fixer) and our unit tests breaking.
Something about the unittest and/or __import__ function breaks,
and since Python 3.1 is so old I'm not going to try to solve it.

Although we're officially supporting Python 3.3 onwards, this
will still work under Python 3.2 which is useful in the short
term for testing PyPy3 (which so far only targets Python 3.2).
Fix stupid mixup in recent commit.
Fix 'import *' (with relative import broke on Jython 2.7b1)
Remove unnecessary some_dict.keys() calls.

For iteration and membership testing can use the
dictionary directly. This also avoids 2to3 adding
list(...) wrappers as list(some_dict.keys()) in
these cases where is it not needed.

Also fixed some white space and string concatenation.
Fix a typo
Tweaking test_Crystal.py to work on Python 3 unmodified
Tweaking test_SeqRecord.py to work on Python 3 unmodified