kebab-case the public interface

I've added a DEPRECATION to all the old names with no particular
time being specified.  I guess I'll give it a month or so.

Closes #29

examples/01_hello_world.p6

@@ -20,7 +20,7 @@ my GTK::Simple::App $app .= new(title => "Hello GTK!");
     all widgets as well as the window. set_content does all of that for us.
 =end comment
 
-$app.set_content(
+$app.set-content(
     GTK::Simple::VBox.new(
         my $button = GTK::Simple::Button.new(label => "Hello World!"),
         my $second = GTK::Simple::Button.new(label => "Goodbye!")
@@ -39,7 +39,7 @@ $app.set_content(
     C<border_width> on a window, however, is special-cased to put
     a border U<inside> the window instead.
 
-$app.border_width = 20;
+$app.border-width = 20;
 
 
 =comment

examples/02_toggles.p6

@@ -16,7 +16,7 @@ my GTK::Simple::App $app .= new(title => "Toggle buttons");
     info to the user and above and below that we create one
     C<GTK::Simple::CheckButton> and a C<GTK::Simple::ToggleButton>.
 
-$app.set_content(
+$app.set-content(
     GTK::Simple::VBox.new(
         my $check_button  = GTK::Simple::CheckButton.new(label => "check me out!"),
         my $status_label  = GTK::Simple::Label.new(text => "the toggles are off and off"),
@@ -29,7 +29,7 @@ $app.set_content(
     Since the window would end up terribly tiny otherwise, we set a
     quite generous inner border for the window
 
-$app.border_width = 50;
+$app.border-width = 50;
 
 =comment
     This sub will be called whenever we toggle either of the two Buttons.

examples/03_grid.p6

@@ -9,7 +9,7 @@ my GTK::Simple::App $app .= new(title => "Grid layouts!");
 =comment
     The interesting bit of this example is the grid constructor.
 
-$app.set_content(
+$app.set-content(
     GTK::Simple::Grid.new(
 =comment
         As you can see, you pass pairs with a coordinate and size on the left
@@ -49,6 +49,6 @@ $app.set_content(
     You can also put grids inside HBox or VBox containers and vice versa.
     This allows for some pretty complex layouts to be created.
 
-$app.border_width = 20;
+$app.border-width = 20;
 
 $app.run;

examples/04_marked_scale.p6

@@ -12,7 +12,7 @@ my %texts = <blue red> Z=>
     '<span foreground="red" size="x-large">Red text</span> is <b>hot</b>!'
 ;
 
-$app.set_content(
+$app.set-content(
     GTK::Simple::VBox.new( 
         GTK::Simple::HBox.new(
             GTK::Simple::VBox.new( 
@@ -69,4 +69,4 @@ $scale-vertical.value-changed.tap: &vertical-changes;
 
 $scale-horizontal.value-changed.tap: &horizontal-changes;
 
-$app.run;
+$app.run;

examples/05_bars.p6

@@ -54,7 +54,7 @@ $button2.clicked.tap({
 my $hbox = GTK::Simple::HBox.new($button1, $button2);
 
 my $frame = GTK::Simple::Frame.new(label => "Status");
-$frame.set_content($status);
+$frame.set-content($status);
 
 
 my $sep1 = GTK::Simple::Separator.new;
@@ -64,8 +64,8 @@ my $vbox = GTK::Simple::VBox.new($hbox,$sep1, $progress, $sep2, $frame);
 
 $vbox.spacing = 10;
 
-$app.set_content($vbox);
+$app.set-content($vbox);
 
-$app.border_width = 20;
+$app.border-width = 20;
 
 $app.run;

examples/06_combo.p6

@@ -3,7 +3,7 @@
 use GTK::Simple;
 
 my $app = GTK::Simple::App.new(title => "Combo Box");
-$app.size_request(300,100);
+$app.size-request(300,100);
 
 my $combo = GTK::Simple::ComboBoxText.new;
 
@@ -18,7 +18,7 @@ $combo.changed.tap({
     $label.text = $combo.active-text();
 });
 
-$app.set_content(GTK::Simple::VBox.new($label, $combo));
+$app.set-content(GTK::Simple::VBox.new($label, $combo));
 
 $app.run;
 

examples/07_text.p6

@@ -20,7 +20,7 @@ $monospace.toggled.tap( -> $w { $text-view.monospace = $w.status });
 
 my $vbox = GTK::Simple::VBox.new($editable, $show-cursor, $monospace, $text-view);
 
-$app.set_content($vbox);
+$app.set-content($vbox);
 
 
 $app.run;