Show chart title for all charts

I implemented a basic title, which show (if defined) the title of the chart.

Title Defaults can be overwritten by adding a 3nd parameter to the "new Chart()" function, which represents the title and adding the showTitle : true to the options.

<pre><code>new Chart(ctx).Bar(data,options,title);</code></pre>

The following defaults can be overridden for the title:

<pre><code>Bar.defaults = {
	//Boolean - Whether to show the title
	showTitle : false,

	//String - Title label font declaration for the title label
	titleFontFamily : "'Arial'",

	//Number - Title label font size in pixels
	titleFontSize : 12,

	//String - Title label font weight style
	titleFontStyle : "normal",

	//String - Scale label font colour
	titleFontColor : "rgba(0, 0, 0, 1)"

}
</code></pre>

See here the example:

![screen shot 2013-05-29 at 17 19 25](https://f.cloud.github.com/assets/382301/579494/40d8468a-c873-11e2-94a8-2043813caf19.png)