Forced build configuration 'Release' on AppVeyor's.

Author: end2endzone

appveyor.yml

@@ -34,6 +34,12 @@ install:
 #       build configuration       #
 #---------------------------------#
 
+# build platform, i.e. x86, x64, Any CPU. This setting is optional.
+#platform: x86
+
+# build Configuration, i.e. Debug, Release, etc.
+configuration: Release
+
 build_script:
 - cmd: call %APPVEYOR_BUILD_FOLDER%\ci\appveyor\build_library.bat
 - cmd: call %APPVEYOR_BUILD_FOLDER%\external\BitReader\ci\appveyor\arduino_library_install.bat