Customized the plugin for the needs of my team

Added the ability to read a configuration file from the OpenCover folder in the solution folder.
That way, the team can customize the command line parameters to do things to exclude/include additional files/assemblies/namespaces/attributes.

I also added the ability to post process the test results and the coverage results.
What I am trying to accomplish here is to generate a HTML result (with my choice of reporting tool) for each.

Here is an example OpenCover.UI.config file which should be placed in the OpenCover folder that is created when OpenCover is run:

<configuration>
  <Parameters>
    <Parameter name="hideskipped">All</Parameter>
    <Parameter name="register">user</Parameter>
    <Parameter name="excludebyattribute">&quot;*.ExcludeFromCodeCoverage*;*.GeneratedCodeAttribute*&quot;</Parameter>
    <Parameter name="filter">&quot;+[*FlashFeed*]* -[*Test]* -&quot;</Parameter>
    <Parameter name="excludebyfile">&quot;*.designer.cs;*.xaml.cs&quot;</Parameter>
  </Parameters>
  <PostProcessors>
    <Command key="testresult">GenerateHtmlTestReport.bat</Command>
    <Command key="coverageresult">GenerateHtmlCoverageReport.bat</Command>
  </PostProcessors>
</configuration>

If I have time, I'd explore adding a UI to edit these, but for now, creating it by hand suits me fine.
Let me know if there are any problems.
Thanks!