Remove warnings-as-errors by default

Compiling C++ on various different platforms with as many out of tree
dependencies as we have is volatile at best.
In order to prevent a third party warning from ruining the build for
people who don't care about third party warnings, we remove
warnings-as-errors by default.
They are still enabled by default on CI.

.appveyor.yml

@@ -13,6 +13,7 @@ environment:
     LLVM_LOC: '"C:\Program Files\LLVM\bin\"'
     PYTHON_LOC: '"C:\Python37\"'
     BUILD_PACKAGE: "1"
+    OVRAS_WARNINGS_AS_ERRORS: "1"
     
   - QT_LOC: '"C:\Qt\5.12\msvc2017_64\bin\"'
     VS_LOC: '"C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvarsall.bat"'
@@ -23,6 +24,7 @@ environment:
     PYTHON_LOC: '"C:\Python37\"'
     BUILD_PACKAGE: "1"
     BUILD_CLANG: '"1"'
+    OVRAS_WARNINGS_AS_ERRORS: "1"
     
 
 clone_depth: 1
@@ -46,4 +48,4 @@ branches:
     - /docs-*/
     - /do-not-run-ci-*/
     - /only-travis-ci-*/
-    - /only-circle-ci-*/
+    - /only-circle-ci-*/