Wrong formatting settings clang-tidy in C++ template project

Closes CWG-48

.clang-tidy

-Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-const-correctness,-misc-unused-parameters,-misc-non-private-member-variables-in-classes,-misc-no-recursion,readability-identifier-naming'
+Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-const-correctness,-misc-unused-parameters,-misc-non-private-member-variables-in-classes,-misc-no-recursion,readability-identifier-naming,readability-braces-around-statements'
 CheckOptions:
   - key:             readability-identifier-naming.ClassCase
     value:           CamelCase
   - key:             readability-identifier-naming.EnumCase
     value:           CamelCase
+  - key:             readability-identifier-naming.UnionCase
+    value:           CamelCase
+# Within ASTRON no specific casing is used. We suggest to use
+# these settings, but feel free to adjust  following casings
+# for existing projects or personal/team preferences.
   - key:             readability-identifier-naming.FunctionCase
-    value:           camelBack
-  - key:             readability-identifier-naming.MemberCase
     value:           CamelCase
+  - key:             readability-identifier-naming.MemberCase
+    value:           lower_case
   - key:             readability-identifier-naming.ParameterCase
-    value:           CamelCase
-  - key:             readability-identifier-naming.UnionCase
-    value:           CamelCase
+    value:           lower_case
   - key:             readability-identifier-naming.VariableCase
-    value:           CamelCase
+    value:           lower_case