Appveyor: Problem with dependencies

XMLBear is skipped on Appveyor Windows builds.
This installs dependencies for lxml.

Fixes coala#1354

.ci/appveyor.yml

@@ -50,6 +50,9 @@ install:
   - "%CMD_IN_ENV% pip wheel --use-wheel --wheel-dir C:\\wheels --find-links C:\\wheels -r requirements.txt"
   - "%CMD_IN_ENV% pip install --find-links=C:\\wheels -r test-requirements.txt"
   - "%CMD_IN_ENV% pip install --find-links=C:\\wheels -r requirements.txt"
+  - "wget https://pypi.python.org/packages/32/a3/396bc886b64e063e2234b9399ad768fdb5b8c42f7e4c784be53089881604/lxml-3.7.2-cp36-cp36m-win_amd64.whl#md5=59dafb956e35d0dbb57d96ad6f5f17d3"
+  - "%CMD_IN_ENV% pip install lxml-3.7.2-cp36-cp36m-win_amd64.whl"
+
   - "CALL .ci/deps.nltk.cmd"
 
   - ps: "Install-Product node ''"  # Use latest node v5.x.x