remove ui namespace which is not really used, move CameraData in camera_modes.h to avoid the inclusion of canva.h

src/texture.h

@@ -11,7 +11,7 @@ class Texture2D
 public:
     bool has_mips = false;
     bool create(int width, int height, GLint internal_format = GL_RGBA8, GLint format = GL_RGBA, const uint8_t* data = nullptr);
-    bool create(const ui::Image& img);
+    bool create(const Image& img);
     void assign(GLuint tex, int w = -1, int h = -1, GLuint internal_format = GL_RGBA8, GLuint format = GL_RGBA);
     bool load(std::string filename);
     bool load_file(std::string filename);