Add CI.

.editorconfig

+# http://editorconfig.org
+root = true
+
+[*]
+indent_style = tab
+indent_size = 4
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = false
+insert_final_newline = true
+
+[*.yml]
+indent_style = space
+indent_size = 2

.gitlab-ci.yml

+stages:
+- test
+
+test:
+  stage: test
+  image: microsoft/dotnet:1.1-sdk-msbuild
+  script:
+  - cd test
+  - dotnet restore
+  - dotnet test | tee tests.out
+  - "cat tests.out | grep 'Failed: 0.'"
+  tags:
+  - Docker