change how origin header is treated

Now check whether the origin is in allowed_origins table,
and if not check allow_all_origins config parameter.

While here:
- add are_cors_preflight_requests_available - if true then preflight
  requests are available (default false)

winixd/core/config.h

@@ -1002,18 +1002,21 @@ public:
 	// if the limit is reached then the http status 503 Service Unavailable is returned
 	size_t request_queue_job_limit;
 
-	// whether or not all origins are allowed in cors requests
-	// default: false;
-	// if false then we check allowed_cors_origins table to check whether the origin is available (origin is sent in Origin header),
-	// if allow_all_cors_origins is false and allowed_cors_origins is empty then by default we do not allow cors requests
-	// (but you can still allow it in your function/controller by overriding IsCorsOriginAvailable(...) method)
-	bool allow_all_cors_origins;
-
 	// list of allowed origins in cors requests
-	// can be set per controller in a method: virtual bool FunctionBase::IsCorsOriginAvailable(const std::wstring & origin_url)
-	// used only if allow_all_cors_origins is false
+	// can be set per controller in a method: virtual bool FunctionBase::IsOriginAvailable(const std::wstring & origin_url)
 	// default: empty
-	std::vector<std::wstring> allowed_cors_origins;
+	std::vector<std::wstring> allowed_origins;
+
+	// whether or not all origins are allowed if allowed_origins is empty
+	// default: true
+	// this is true by default because Origin header is sent not only in cors requests
+	// (you can still allow it in your function/controller by overriding IsOriginAvailable(...) method)
+	bool allow_all_origins;
+
+	// whether or not cors preflight requests are available
+	// https://developer.mozilla.org/en-US/docs/Glossary/Preflight_request
+	// default: false
+	bool are_cors_preflight_requests_available;
 
 	// list of additional headers sent in Access-Control-Expose-Headers header
 	// can be set per controller in a method: virtual void FunctionBase::AddAccessControlExposeHeadersHeader()