Add rasterization to bitmap to sixel.

src/fonts.rs

@@ -0,0 +1,10 @@
+use fontdue::Font;
+use lazy_static::lazy_static;
+
+pub static KaTeX_Main_Regular: &'static [u8] = include_bytes!("../fonts/KaTeX_Main-Regular.ttf");
+
+lazy_static! {
+    pub static ref FONTS: Vec<Font> = vec![
+        Font::from_bytes(KaTeX_Main_Regular, fontdue::FontSettings::default()).unwrap(),
+    ];
+}