Provide a semantics-only configuration

* configure style rules as warnings
    * configure rules that can introduce semantic errors as errors

docs/configuration.rst

@@ -43,6 +43,19 @@ It can be chosen using:
 
  yamllint -d relaxed file.yml
 
+There is another pre-defined configuration named ``semantics-only``.
+As its name suggests, it is more tolerant:
+
+.. literalinclude:: ../yamllint/conf/semantics-only.yaml
+   :language: yaml
+
+It can be chosen using:
+
+.. code:: bash
+
+ yamllint -d semantics-only file.yml
+
+
 Extending the default configuration
 -----------------------------------
 

yamllint/conf/semantics-only.yaml

@@ -0,0 +1,46 @@
+---
+
+extends: default
+
+rules:
+  braces:
+    level: warning
+  brackets:
+    level: warning
+  colons:
+    level: warning
+  commas:
+    level: warning
+  comments:
+    level: warning
+  comments-indentation:
+    level: warning
+  document-end:
+    level: warning
+  document-start:
+    level: warning
+  empty-lines:
+    level: warning
+  empty-values:
+    level: warning
+  hyphens:
+    level: warning
+  indentation:
+    level: warning
+  key-duplicates: enable
+  key-ordering:
+    level: warning
+  line-length:
+    level: warning
+  new-line-at-end-of-file:
+    level: warning
+  new-lines:
+    level: warning
+  octal-values:
+    level: warning
+  quoted-strings:
+    level: warning
+  trailing-spaces:
+    level: warning
+  truthy:
+    level: error