Dmx512 and Ws2821 for ESP8266 (#565)

* refactor esp8266 DMA core
* refactor NeoUtil
* DMX512
* WS2821

src/internal/NeoEsp8266I2sMethodCore.cpp

@@ -0,0 +1,34 @@
+/*-------------------------------------------------------------------------
+NeoPixel library helper functions for Esp8266.
+
+Written by Michael C. Miller.
+
+I invest time and resources providing this open source code,
+please support me by dontating (see https://github.com/Makuna/NeoPixelBus)
+
+-------------------------------------------------------------------------
+This file is part of the Makuna/NeoPixelBus library.
+
+NeoPixelBus is free software: you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as
+published by the Free Software Foundation, either version 3 of
+the License, or (at your option) any later version.
+
+NeoPixelBus is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with NeoPixel.  If not, see
+<http://www.gnu.org/licenses/>.
+-------------------------------------------------------------------------*/
+
+#include <Arduino.h>
+#include "NeoEsp8266I2sMethodCore.h"
+
+#ifdef ARDUINO_ARCH_ESP8266
+
+NeoEsp8266I2sMethodCore* NeoEsp8266I2sMethodCore::s_this;
+
+#endif