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

src/image.cpp

@@ -5,8 +5,6 @@
 
 #include <stb/stb_image.h>
 
-using namespace ui;
-
 bool Image::load(std::string filename)
 {
     stbi_set_flip_vertically_on_load(false);
@@ -47,7 +45,7 @@ void Image::flip()
     std::swap(m_data, flipped);
 }
 
-ui::Image ui::Image::resize(int w, int h)
+Image Image::resize(int w, int h)
 {
     Image ret;
     ret.create(w, h);