[NPANDAY-578] correct resolution logic

MSBuild has a second target that will override other paths, which is how the reference assemblies are found. 
Included that in the process, and corrected some logic to ensure all the relevant versions are consulted.


git-svn-id: https://svn.apache.org/repos/asf/incubator/npanday/trunk@1452306 13f79535-47bb-0310-9956-ffa450edef68