clean up files, parse arguments with clap

src/window_size.rs

@@ -0,0 +1,17 @@
+use crate::BYTES_PER_LINE;
+
+#[derive(Clone, Copy)]
+pub struct WindowSize {
+	pub rows: usize,
+	pub covered_rows: usize,
+}
+
+impl WindowSize {
+	pub const fn visible_byte_count(&self) -> usize {
+		self.hex_rows() * BYTES_PER_LINE
+	}
+	
+	pub const fn hex_rows(&self) -> usize {
+		self.rows - self.covered_rows
+	}
+}