Don't copy the .addin.xml to the output dir

There is no need to copy the addin.xml file. The mpack can be
generated from the compiled add-in assembly.
Use an msbuild task to copy the AspNetMvc4 files to the output

On Windows we don't use the makefile, so the files were not
copied.
Merge pull request #208 from slluis/path-fix

Fixed a couple of build issues