Duplicate % not working in C#

[jonathanmccracken]

Description

Sometimes the duplicates in C# are way over 100% because cpd doesn't exclude the ignored assemblies/directories.

Steps to Reproduce

1. Run a c# project
2. Ignore some assemblies that have large subdirectories of source code
3. Watch duplicates go way off the charts

Metropolis Version: 0.0.68
Operating System (i.e. Windows) Version: Windows 10

[jonathanmccracken]

Try to expand Greg's .ignore file to include directories
modify cpd to use:
--exclude Files to be excluded from CPD check
https://pmd.github.io/pmd-5.4.1/usage/cpd-usage.html

Supports directories apparently...
https://github.com/pmd/pmd/blob/master/pmd-core/src/main/java/net/sourceforge/pmd/cpd/CPDConfiguration.java#L296

Potentially add C#'s '--ignore-usings' since we don't want to report duplicate using blocks in our numbers