fix warnings + cland-tidy

.clang-tidy

@@ -0,0 +1,27 @@
+Checks: >-
+  -*,
+  readability-identifier-naming,
+  readability-redundant-string-cstr,
+  readability-redundant-string-init,
+  readability-simplify-boolean-expr,
+  performance-unnecessary-value-param,
+  performance-unnecessary-copy-initialization,
+  performance-for-range-copy,
+  performance-implicit-conversion-in-loop,
+CheckOptions:
+- key:             readability-identifier-naming.PrivateMemberPrefix
+  value:           'm_'
+- key:             readability-identifier-naming.ClassConstantCase
+  value:           aNy_CasE
+# an empty *Prefix needs a *Case to work
+- key:             readability-identifier-naming.ClassConstantPrefix
+  value:           ''
+#- key:             readability-identifier-naming.PrivateMemberCase
+#  value:           CamelCase
+#- key:             readability-identifier-naming.FunctionCase
+#  value:           CamelCase
+#- key:             readability-identifier-naming.EnumCase
+#  value:           camelBack
+
+WarningsAsErrors: '*'
+FormatStyle: 'file'