Aesthetic miscellany.
We'll now use virtualenv > base path by default.

Erik's was a good idea about configuring the base path for virtualenvs, so I
made it the default way to handle it.

However, the config template will use virtualenvwrappers default location
because it's a widely used tool.
Support Python 2 and 3.
Reorganization in preparation for a major overhaul.

I used distutils before because I always prefer core packages to third-party
libraries. However, distutils isn't sufficient and the...well, the whole thing
sickens me, actually. Packaging in Python is not Pythonic.
Rewrote almost everything.

I need to port the important function, the one that actually manipulates tmux.
This is a pretty good method of handling the configuration, though some things
are still bothering me.
Re-implemented the start command.

It's a bit nicer than the original, but I'll be doing some more clean up.
Altered access to the run context.
Switch sessions when inside a tmux session.

Fixes #4
Made the verbosity configurable.

Setting the TENPER_VERBOSE environment variable to 'true' will cause tenper to
print out all the commands it executes.
Added project classifiers.
Version bump; added a change log (changes.rst).
Added TENPER_VIRTUALENV to tenper sessions.

This is the path to the virtualenv activate script. I'm not going to document
this at the moment because I'm mulling stuff over.

I use this because we can't automatically source this script for every new
pane. It might be nice instead to augment the tenper commands with stuff like:

  tenper source-virtualenv
  tenper new-window
Fixed circular import errors.

These didn't show up when testing in iPython. Anyway, by 'fixed' I mean I
hacked it. Everyone says these point to bad code organization and I now see
that they're right, but I hate that monolithic file I had before.

I need to rework it. There's a distinction here that I'm missing.
Clarified documentation.
Fixed circular imports with a hack.

I'll rework everything again, eventually.
Reimplemented the 'completions' command.
Aesthetic changes to the default template.
Fixed the 'edit' command.

The subprocess commands that return output are appropriate for executing a
child editor process. I added a flag to distinguish 'interactive' commands.
Aesthetics.
Fixed virtualenv sourcing.