Added appveyor config file

appveyor.yml

@@ -1,7 +1,5 @@
 before_build:
-- mkdir ./build
-- cd ./build
-- cmake -DGLM_TEST_ENABLE=ON -DGLM_TEST_ENABLE_CXX_98=ON ..
+- cmake -DGLM_TEST_ENABLE=ON -DGLM_TEST_ENABLE_CXX_98=ON .
 
 build_script:
   - cmake --build .