ci(enc, win): set unicode in TEMP env-var

Trick picked up from gitpython-developers#543. [travis skip]

Author: ankostis

.appveyor.yml

@@ -3,6 +3,7 @@ environment:
     GIT_DAEMON_PATH:   "C:\\Program Files\\Git\\mingw64\\libexec\\git-core"
     CYGWIN_GIT_PATH:   "C:\\cygwin\\bin;%GIT_DAEMON_PATH%"
     CYGWIN64_GIT_PATH: "C:\\cygwin64\\bin;%GIT_DAEMON_PATH%"
+    TMPDIR: "%TMP%\\καλημέρα"
 
     matrix:
         ## MINGW
@@ -35,17 +36,19 @@ environment:
 
 
 install:
+    - md "$TMPDIR"
     - set PATH=%PYTHON%;%PYTHON%\Scripts;%GIT_PATH%;%PATH%
 
     ## Print configuration for debugging.
     #
     - |
-        echo %PATH%
+        set
         uname -a
         git --version
         where git git-daemon python pip pip3 pip34
         python --version
         python -c "import struct; print(struct.calcsize('P') * 8)"
+        python -c "import tempfile; print(tempfile.mktemp())"
 
     - IF "%IS_CONDA%" == "yes" (
         conda info -a &