Custom %PROGRAM_FILES% directory

[iliapolo]

Currently, the windows installer created by PyCI is configured to always place the installation under: %PROGRAM_FILES%\%PACKAGE_NAME%.

(The %PACKAGE_NAME% is extracted form the name argument of the setup.py file)

For example, PyCI is placed under: %PROGRAM_FILES%\py-ci.

While this makes sense, sometimes the user needs ability to specify a custom program files directory.

For example, imagine the following use case:

1. Application my-app is installed under directory my-app-win.
2. The owner of the application now migrates to PyCI, which creates an installer for him.
3. The installer is published, but installs the application under the my-app directory.

This causes the new installation not to override the existing one, which breaks the installation contract.

Specifying a custom program files directory will solve this problem since the owner of my-app will configure the installer to install under my-app-win.

[iliapolo]

This issue is part of release 0.8.2