Convert .tgs with go libraries (and cgo) (telegram) (#1569)

This commit adds support for go/cgo tgs conversion when building with the -tags `cgo`
The default binaries are still "pure" go and uses the old way of converting.

* Move lottie_convert.py conversion code to its own file

* Add optional libtgsconverter

* Update vendor

* Apply suggestions from code review

* Update bridge/helper/libtgsconverter.go

Co-authored-by: Wim <wim@42.be>

vendor/github.com/Benau/go_rlottie/vector_vbitmap.h

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) 2020 Samsung Electronics Co., Ltd. All rights reserved.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef VBITMAP_H
+#define VBITMAP_H
+
+#include "vector_vrect.h"
+#include "vector_vsharedptr.h"
+
+V_BEGIN_NAMESPACE
+
+class VBitmap {
+public:
+    enum class Format: uchar {
+        Invalid,
+        Alpha8,
+        ARGB32,
+        ARGB32_Premultiplied
+    };
+
+    VBitmap() = default;
+    VBitmap(size_t w, size_t h, VBitmap::Format format);
+    VBitmap(uchar *data, size_t w, size_t h, size_t bytesPerLine, VBitmap::Format format);
+    void reset(uchar *data, size_t w, size_t h, size_t stride, VBitmap::Format format);
+    void reset(size_t w, size_t h, VBitmap::Format format=Format::ARGB32_Premultiplied);
+    size_t          stride() const;
+    size_t          width() const;
+    size_t          height() const;
+    size_t          depth() const;
+    VBitmap::Format format() const;
+    bool            valid() const;
+    uchar *         data();
+    uchar *         data() const;
+    VRect           rect() const;
+    VSize           size() const;
+    void    fill(uint pixel);
+    void    updateLuma();
+private:
+    struct Impl {
+        std::unique_ptr<uchar[]> mOwnData{nullptr};
+        uchar *         mRoData{nullptr};
+        uint            mWidth{0};
+        uint            mHeight{0};
+        uint            mStride{0};
+        uchar           mDepth{0};
+        VBitmap::Format mFormat{VBitmap::Format::Invalid};
+
+        explicit Impl(size_t width, size_t height, VBitmap::Format format)
+        {
+            reset(width, height, format);
+        }
+        explicit Impl(uchar *data, size_t w, size_t h, size_t bytesPerLine, VBitmap::Format format)
+        {
+            reset(data, w, h, bytesPerLine, format);
+        }
+        VRect   rect() const { return VRect(0, 0, mWidth, mHeight);}
+        VSize   size() const { return VSize(mWidth, mHeight); }
+        size_t  stride() const { return mStride; }
+        size_t  width() const { return mWidth; }
+        size_t  height() const { return mHeight; }
+        uchar * data() { return mRoData ? mRoData : mOwnData.get(); }
+        VBitmap::Format format() const { return mFormat; }
+        void reset(uchar *, size_t, size_t, size_t, VBitmap::Format);
+        void reset(size_t, size_t, VBitmap::Format);
+        static uchar depth(VBitmap::Format format);
+        void fill(uint);
+        void updateLuma();
+    };
+
+    rc_ptr<Impl> mImpl;
+};
+
+V_END_NAMESPACE
+
+#endif  // VBITMAP_H