#7 Path doesn't use project basedir

[Colin Svingen]

When doing a nested build the 'todir' attribute is not
taking into account the project's basedir. The path is,
instead, being calculated with the location of the build
file as the root.

I hacked my version so that the path is calculated
correctly with the following code:
/// <summary>
/// The directory where the files resulting from the
transformation should be written to.
/// </summary>
[TaskAttribute("todir", Required=false)]
public string Todir {
get { return _todir; }
set { _todir = Path.GetFullPath(Path.Combine
(Project.BaseDirectory, value)); }
}

This is a regression bug as previous versions didn't have
this problem.