Minor improvements to Vagrant configuration

devtools/packaging/scripts/windows/prepare.ps1

 cd C:\Users\vagrant
 
-# Install everything we can with choco.
-
-choco install -y doxygen.portable swig cmake doxygen.install vcbuildtools git jom
-
 # Install CUDA.
 
 wget https://developer.nvidia.com/compute/cuda/8.0/prod/network_installers/cuda_8.0.44_win10_network-exe -UseBasicParsing -OutFile cuda_8.0.44_win10_network.exe
@@ -21,5 +17,9 @@ wget https://repo.continuum.io/miniconda/Miniconda3-latest-Windows-x86_64.exe -U
 
 # Install software with conda.
 
-& "C:\Miniconda3\Scripts\conda.exe" install -y -c omnia fftw3f jinja2 lxml sphinx sphinxcontrib-autodoc_doxygen sphinxcontrib-lunrsearch conda-build
+& "C:\Miniconda3\Scripts\conda.exe" install -y -c omnia fftw3f jinja2 lxml sphinx sphinxcontrib-autodoc_doxygen sphinxcontrib-lunrsearch conda-build anaconda-client
 & "C:\Miniconda3\Scripts\pip.exe" install sphinxcontrib.bibtex
+
+# Install software with choco.
+
+choco install -y doxygen.portable swig cmake doxygen.install vcbuildtools git jom