Fix a leftover x,y stroke on circles

Fixes #35

lib/squib/graphics/shapes.rb

@@ -21,6 +21,7 @@ module Squib
     # @api private
     def circle(x, y, radius, fill_color, stroke_color, stroke_width)
       use_cairo do |cc|
+        cc.move_to(x,y)
         cc.circle(x, y, radius)
         cc.set_source_squibcolor(stroke_color)
         cc.set_line_width(stroke_width)

spec/data/samples/draw_shapes.rb.txt

@@ -8,6 +8,7 @@ cairo: set_source_color([:blue])
 cairo: fill([])
 cairo: restore([])
 cairo: save([])
+cairo: move_to([600, 600])
 cairo: circle([600, 600, 75])
 cairo: set_source_color([:green])
 cairo: set_line_width([8.0])

spec/data/samples/gradients.rb.txt

@@ -10,6 +10,7 @@ cairo: set_line_width([15])
 cairo: stroke([])
 cairo: restore([])
 cairo: save([])
+cairo: move_to([415, 415])
 cairo: circle([415, 415, 100])
 cairo: set_source_color(["#0000"])
 cairo: set_line_width([2.0])

spec/graphics/graphics_shapes_spec.rb

@@ -34,6 +34,7 @@ describe Squib::Card do
   context 'circle' do
     it 'make all the expected calls on a smoke test' do
       expect(@context).to receive(:save).once
+      expect(@context).to receive(:move_to).with(37, 38)
       expect(@context).to receive(:circle).with(37, 38, 100).twice
       expect_stroke('#fff', '#f00', 2.0)
       expect(@context).to receive(:restore).once