Added line cap and join settings for rect and curve

More forthcoming - these are proof-of-concept

samples/draw_shapes.rb

@@ -2,8 +2,12 @@ require 'squib'
 
 Squib::Deck.new do
   background color: :white
+
+  rect x: 300, y: 100, width: 200, height: 50
+
   rect x: 300, y: 300, width: 400, height: 400,
-       fill_color: :blue, stroke_color: :red, stroke_width: 50.0
+       fill_color: :blue, stroke_color: :red, stroke_width: 50.0,
+       join: 'bevel'
 
   circle x: 600, y: 600, radius: 75,
          fill_color: :gray, stroke_color: :green, stroke_width: 8.0
@@ -13,7 +17,6 @@ Squib::Deck.new do
            x3: 75, y3: 250,
            fill_color: :gray, stroke_color: :green, stroke_width: 3.0
 
-
   line x1: 50, y1: 550,
        x2: 150, y2: 650,
        stroke_width: 25.0
@@ -21,7 +24,7 @@ Squib::Deck.new do
   curve x1: 50,  y1: 850, cx1: 150, cy1: 700,
         x2: 625, y2: 900, cx2: 150, cy2: 700,
         stroke_width: 12.0, stroke_color: :cyan,
-        fill_color: :burgundy
+        fill_color: :burgundy, cap: 'round'
 
   ellipse x: 50, y: 925, width: 200, height: 100,
           stroke_width: 5.0, stroke_color: :cyan,