The new wizard walks the user through installing Review Board via the

following steps:


Showing an overview of the install process, along with the system and

   target version information, and confirming before moving on.


Displays details on the Site vs. Install Directories, asks the user

   for the install location for the virtualenv, and validates the path.


Shows the commands that will be run and then prompts for confirmation

   before installing.


Performs the install, streaming results and showing progress.


Asks the user if they want to create a new sitedir or import one, and

   walks the user through those choices.


If requested, executes rb-site install to help the user install the

   site.


Finishes up with a success or error result, and any further steps

   that may be needed.


This makes the install process very simple, and gives users just enough

information to make the right choices.
Right now, the wizard is not invoked. That will be handled in the next

change.

Extensively tested the wizard in both interactive and unattended modes.

Tested validation and error handling, and different install state for

installation options. Completed several installs.