Phylo: replaced all iterable.next() calls with next(iterable)

For future Python 3 compat. Python 2.6 introduced the next() function.
Re-raise exception rather than triggering divide by zero; print functions
Use next(iterator) in SeqIO, AlignIO and SearchIO

This is for better Python 3 compatibility, the built in function
next() was added in Python 2.6 and allows next(iterator) in place
of iterator.next() which is not allowed on Python 3.
Remove a resolved TODO comment
Replace some uses of map with list comprehensions.

This is a little tweak for better cross-compatibility with
the same code under Python 2 (where map gives a list) and
Python 3 (where map gives an iterator).
Add missing copyright & license text to many unit tests
Adjust sorting of dictionary keys etc for Python 3.

On Python 2 my_dict.keys() is a list so has a .sort() method.
On Python 3 my_dict.keys() is an iterator so use sorted() function.
Fix some print statements/functions to work on both Python 2 & 3
Avoid my_dict.iteritems() in tests for Python 3 compatibility.

Using the iterator method is more memory efficient,
but for the unit tests this doesn't matter and I would
rather have the same code work under both Python 2 and 3.
Avoid another my_dict.iteritems() in tests for Py3 compatibility
Update StringIO/BytesIO imports in run_tests.py

This is enough to run this file unmodified on both Python 2.6+
and Python 3.3
Implement StringIO import via Bio._py3k module

The goal here is to facilitate writing code which can be
run on both Python 2 and Python 3 without alteration via
2to3 (and fixing these imports currently needs 2to3).
Import StringIO via _py3k module in tests
Remove unused StringIO import
Import StringIO via Bio._py3k
Deprecate Bio.ParserSupport & Bio.Blast.NCBIStandalone
Silence plain text BLAST parser deprecation warning in SearchIO
Consistent full stops in README file.
Switching README from markdown to rst

GitHub supports both, but PyPI only supports reStructuredText.
We're also aiming to move to reStructuredText for docstrings etc.
Use Python 3 style print function in the Tutorial.

This is a step towards Python 3, we can already use
the print function under Python 2.6 and 2.7 via:

from __future__ import print_statement

TODO: Add an FAQ to the Tutorial explaining why we're
doing this.