Major 0.2.0 update.

Replace PyQt4 with PySide.
Add esky support with updater that checks for new versions using a proxy
aware internet connection.
Add utility to check for duplicate calculations.
Remove UTR measures for periods of time since they shouldn't be used on
their own.
Add Inno Setup script for generating an installer.
Use a try catch statement for file opening, which prints an error
message to the status bar if the selected file cannot be opened.
List extended measures that haven't been changed when the the Comply
with UTR utility is run.
Fix UTR Ton/Tonne bug.

Previously, an extended measure of "abc:T" (Tonne) would be changed to
"utr:t" (Ton) before being correctly set to "utr:T" (Tonne). This commit
makes it change directly to "utr:T" (Tonne).
Update TODO.md
Add durational UTR measures to units.ini

Add measures for years, months, days, hours, minutes, and seconds to
units.ini.
Load about view at application launch.
Remove update functionality.

The esky application updater doesn't work on Windows 7 and above. A more
ideal updater can be created using Inno Setup and a version file hosted
on a server.

While the Inno updater won't be written for sometime, I believe it's
best to to remove the esky updater for now, so that deployment is
consistent across Windows versions and so that the thinX may be deployed
on systems running Python 3.3.
Remove update function from menu and rebuild UI.

The update function is no longer in the project, so the option under the
help menu has been deleted. Also, the UI and it's resources have been
rebuilt using PySide.
Remove esky.

Dropping esky andthe build process allows the project to work on Python
3.3.
Add __init__.py.

This will be necessary for running tests from within subfolders. The
project directory will also need to be added to $PYTHONPATH in order for
this to work.
Add Python gitignore.