continued to work on new UI library

- implemented CgStatusBar widget which is a specific version of the CgIndicatorBar widget with predefined fields

- std::io::Screen is now an enum that makes switching between display modes more intuitive

- created a basic CgLineEdit implementation that allows for a user to type in a character and have it re-render that widget

- other more minor changes like fixes for existing apps to work with new features

src/user/lib/libgui/cg_inputs.rs

@@ -0,0 +1,53 @@
+use alloc::string::String;
+use alloc::vec::Vec;
+use crate::std::frame::{ColouredChar, Dimensions, Frame, Position, RenderError};
+use crate::user::lib::libgui::cg_core::{CgComponent, CgTextEdit};
+
+pub struct CgLineEdit {
+    pub position: Position,
+    pub dimensions: Dimensions,
+    pub prompt: String,
+    pub text: Vec<char>,
+    pub ptr: usize, // cursor position
+}
+
+impl CgLineEdit {
+    pub fn new(position: Position, width: usize, prompt: String) -> CgLineEdit {
+        CgLineEdit {
+            position,
+            dimensions: Dimensions::new(width, 1),
+            prompt: prompt,
+            text: Vec::new(),
+            ptr: 0
+        }
+    }
+}
+
+impl CgComponent for CgLineEdit {
+    fn render(&self) -> Result<Frame, RenderError> {
+        let mut frame = Frame::new(self.position, self.dimensions)?;
+
+        let mut ptr = 0;
+
+        for c in self.prompt.chars() {
+            if ptr >= self.dimensions.x {
+                break;
+            }
+            frame.write(Position::new(ptr, 0), ColouredChar::new(c));
+            ptr += 1
+        }
+
+        ptr += 1; // create a space between the prompt and the text
+
+        for c in self.text.iter() {
+            if ptr >= self.dimensions.x {
+                break;
+            }
+            frame.write(Position::new(ptr, 0), ColouredChar::new(*c));
+            ptr += 1
+        }
+
+        Ok(frame)
+    }
+}
+