Update .travis.yml and appveyor.yml to build quietly.

Author: N. Taylor Mullen

.travis.yml

@@ -1,4 +1,4 @@
 language: csharp
 sudo: false
 script:
-  - ./build.sh verify
+  - ./build.sh --quiet verify

appveyor.yml

@@ -1,7 +1,7 @@
 init:
   - git config --global core.autocrlf true
 build_script:
-  - build.cmd verify
+  - build.cmd --quiet verify
 clone_depth: 1
 test: off
 deploy: off