Merge pull request #9 from tseaver/tseaver-gut_meld3_submodule

Move all logic into '__init__.py'.
Unused alias.
Don't rely on 'basestring'.
Incremental clarity on text vs. bytes.
Remove muddying ASCII-only 'optimization'.
Rip out preferred import of 'elementtree.ElementTree.*'.

Use the stdlib 'xml.elementtree.ElementTree' imports.
Move version-compat stuff into 'meld3._compat'.

Except the ambiguous 'encode()', which needs clarity first.
Remove fossil 'IO' class.
Ensure that 'encode()' and related always return bytes.

Ensure that operations writing to a stream always write bytes.
Merge pull request #10 from tseaver/master

Get tests passing on Python 3.2
Prune MeldParser to essentials (hide on Python >= 2.7).

- Move check for duplicate meldids into the TreeBuilder, where the
  API wants it (Python 3.3 doesn't call our '_start_list').

- Drop custom '__init__', '_start*', and 'close' accordingly.

- Just use stock XMLParser for Python 2.7+, because it already does
  what we need for comments.

Tests now pass on Python 3.3.
Merge pull request #11 from tseaver/master

Prune MeldParser to essentials (hide on Python >= 2.7).
Credit Tres Seaver for Python 3 support in the changelog
Add classifiers for Python 3
Remove example.py and melddiff.py
Remove support for ``python meld3.py <file> <mutator>``