[NPANDAY-578] relativize paths within the project

Primarily for packages downloaded using NuGet, this will make libraries a little more portable
if they continue to use the system path.


git-svn-id: https://svn.apache.org/repos/asf/incubator/npanday/trunk@1452308 13f79535-47bb-0310-9956-ffa450edef68