Remove nalgebra dependency

- Implement our own `Point` and `Vector` types
  - Make `Rectangle` not generic

examples/ggez/renderer/button.rs

@@ -29,7 +29,7 @@ impl button::Renderer for Renderer<'_> {
     fn draw(
         &mut self,
         cursor_position: iced::Point,
-        mut bounds: iced::Rectangle<f32>,
+        mut bounds: iced::Rectangle,
         state: &button::State,
         label: &str,
         class: button::Class,

examples/ggez/renderer/checkbox.rs

@@ -14,8 +14,8 @@ impl checkbox::Renderer for Renderer<'_> {
     fn draw(
         &mut self,
         cursor_position: iced::Point,
-        bounds: iced::Rectangle<f32>,
-        text_bounds: iced::Rectangle<f32>,
+        bounds: iced::Rectangle,
+        text_bounds: iced::Rectangle,
         is_checked: bool,
     ) -> MouseCursor {
         let mouse_over = bounds.contains(cursor_position)

examples/ggez/renderer/radio.rs

@@ -14,8 +14,8 @@ impl radio::Renderer for Renderer<'_> {
     fn draw(
         &mut self,
         cursor_position: Point,
-        bounds: Rectangle<f32>,
-        bounds_with_label: Rectangle<f32>,
+        bounds: Rectangle,
+        bounds_with_label: Rectangle,
         is_selected: bool,
     ) -> MouseCursor {
         let mouse_over = bounds_with_label.contains(cursor_position);

examples/ggez/renderer/slider.rs

@@ -22,7 +22,7 @@ impl slider::Renderer for Renderer<'_> {
     fn draw(
         &mut self,
         cursor_position: Point,
-        bounds: Rectangle<f32>,
+        bounds: Rectangle,
         state: &slider::State,
         range: RangeInclusive<f32>,
         value: f32,

examples/ggez/renderer/text.rs

@@ -69,7 +69,7 @@ impl text::Renderer<Color> for Renderer<'_> {
 
     fn draw(
         &mut self,
-        bounds: iced::Rectangle<f32>,
+        bounds: iced::Rectangle,
         content: &str,
         size: f32,
         color: Option<Color>,