Test the vga buffer module through a print_something function

src/vga_buffer.rs

@@ -85,3 +85,15 @@ impl Writer {
 
     fn new_line(&mut self) {/* TODO */}
 }
+
+pub fn print_something() {
+    let mut writer = Writer {
+        column_position: 0,
+        color_code: ColorCode::new(Color::Yellow, Color::Black),
+        buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
+    };
+
+    writer.write_byte(b'H');
+    writer.write_string("ello ");
+    writer.write_string("Wörld!");
+}