Modify paths in build scripts

(convert MSBuildTasks NuGet package to simple build directory)
Merge branch 'dev'
Create /build/out dir via Build.proj

Set the out directory to be ignored and will be the future home of all build output (test results, packages, etc).
Change RunUnitTest target to use /build/out

Also removing TestResults.xml from .gitignore since /build/out is already being ignored.
Merge branch 'dev'