Uninstall MSBuildTasks NuGet package

(convert MSBuildTasks NuGet package to simple build directory)
This is the first step in converting the MSBuildTasks NuGet package and associated build scripts to a stand-along /build directory.
Remove .build solution folder

(convert MSBuildTasks NuGet package to simple build directory)
Move build dir to root

(convert MSBuildTasks NuGet package to simple build directory)
/src/.build -> /build
Move .proj build scripts to /build

(convert MSBuildTasks NuGet package to simple build directory)
Adjust build scripts for new path

(convert MSBuildTasks NuGet package to simple build directory)
Modify build.cmd to point to Build.proj in /build vs. /src.
Modify Build.proj to reference soltuion source and binaries in new relative locations.