feat(render): style, GLSL line/text pipelines, staging batches, bitmap font

CMakeLists.txt

@@ -13,6 +13,12 @@ add_library(plot_core
   src/data/stream_series.cpp
   src/gl/loader.cpp
   src/gl/handle.cpp
+  src/render/shaders.cpp
+  src/render/bitmap_font.cpp
+  src/render/primitives.cpp
+  src/render/buffer.cpp
+  src/render/vertex_array.cpp
+  src/render/program.cpp
 )
 add_library(plot::core ALIAS plot_core)