Drop heavy python dependency, change project folder.

See #110. [skip ci]

.appveyor.yml

+clone_folder: "C:\msys64\home\ghc\shake-build"
+
 install:
     - set MSYSTEM=MINGW64
     - set PATH=C:\msys64\mingw64\bin;C:\msys64\usr\local\bin;C:\msys64\usr\bin;%PATH%
-    - bash -lc "pacman -S --noconfirm git binutils p7zip gcc mingw-w64-$(uname -m)-python3-sphinx"
+    - bash -lc "pacman -S --noconfirm git binutils p7zip gcc"
     - bash -lc "curl -LsS http://www.haskell.org/ghc/dist/7.10.1/ghc-7.10.1-x86_64-unknown-mingw32.tar.xz | tar -xJ -C /mingw64 --strip-components=1"
     - bash -lc "mkdir /usr/local"
     - bash -lc "mkdir /usr/local/bin"