Tell AppVeyor to install the FBX SDK from elsewhere (#201)

We'll fetch release tarballs from another GitHub repo.

appveyor.yml

@@ -10,9 +10,20 @@ environment:
 stack: python %PYTHON%
 
 cache:
-  - C:\Users\appveyor\.conan\data -> appveyor.yml
+  - C:\Users\appveyor\.conan\data -> appveyor.yml, conanfile.py
+
+init:
+  - git config --global filter.lfs.required false
+  - git config --global filter.lfs.smudge "git-lfs smudge --skip %f"
+  - git config --global filter.lfs.process "git-lfs filter-process --skip"
 
 install:
+  - cinst zstandard
+  - ps: Start-FileDownload 'https://github.com/zellski/FBXSDK-Windows/archive/2019.2.tar.gz'
+  - 7z e 2019.2.tar.gz
+  - 7z x 2019.2.tar
+  - ps: move -v .\FBXSDK-Windows-2019.2\sdk\ .
+  - ps: zstd -d -r --rm sdk
   - cmd: echo "Downloading conan..."
   - cmd: set PATH=%PYTHON%;%PYTHON%\Scripts;%PATH%
   - cmd: python --version