Line Point Hover Implementation, Styling and JavaScript Events

Added mouseover colors as well as firing off JavaScript events on mouseover and mouseout for line points. Also changed the constructor so just the element is passed and not the context, otherwise you cannot attach the listener event.

This is something I did over the weekend.

I changed the constructor so that you have to pass the element rather than the context, and the code will automatically obtain the context from the element.

I had to do this otherwise I have no idea (code wise) what I need to bind the listener event to.

Now I knew doing this might go against the grain and won't be accepted, if it's not, then I will just simply make a spin off for myself and others to use, but I wanted to give it a shot to see if it would be accepted.

I also plan to implement this for Bars and other charts, just haven't gotten around to it yet.


Usage Example:
```json
			var data = {
				labels : ["January","February","March","April","May","June","July"],

				datasets : [
					{
						fillColor : "rgba(220,220,220,0.5)",
						strokeColor : "rgba(220,220,220,1)",
						pointColor : "rgba(220,220,220,1)",
						pointStrokeColor : "#fff",

						pointColorHover : "rgba(255,187,205,1)",
						pointStrokeColorHover : "rgba(255,187,205,1)",
						pointDotStrokeWidthHover : "rgba(255,187,205,1)",
						
						data : [65,59,90,81,56,55,40],

						mouseover: function(data) {
							console.log(data);
							console.log('over: look at me im in the data code!')
						},

						mouseout: function(data) {
							console.log(data);
							console.log('out: ook at me im in the data code!')
						}
					}
				]
			}
```