FIX: Ensure pip is installed in conda environment

Author: effigies

appveyor.yml

@@ -22,6 +22,7 @@ install:
   - SET PATH=%PYTHON%;%PYTHON%\Scripts;%PATH%
 
   # Install the dependencies of the project.
+  - conda install -y pip
   - python -m pip install --upgrade pip setuptools wheel
   - python -m pip install numpy scipy matplotlib nose h5py mock pydicom
   - python -m pip install .