Added offset x/y functionality, screen detection

1. Added offset x/y for additional placement options
2. Put in screen detection mode so that it will stay on screen by default
Added default styling

1. Ensured the li width is filled out properly
2. Adjusted the separator so that it uses a border instead of showing the hr tag, this displays better and is how they do their separators in the normal menu
Switched from items to dataSource, added mouse leave/enter events

1. Switched to dataSource instead of items, this way the menu will automatically render nested items. Before it would not render the nested menu structure because the html was being formed manually.
1a. side effect of this is I could not get the iconCss to work and insert template correctly but you can use the ImageUrl to add images as needed.

2. Added mouse leave/enter to hide/keep showing the menu as needed
changed document.click to document.on("click")
on document.click, let the control dictate if needed to hide

When adding this menu to a grid it was not hiding properly so I shifted away from the k-custom-visible class check to the shown widget variable
switched to kendo fadein/fadeout for show/hide animations

The jquery toggle was finicky and sometimes not consistent.
Made a custom data object available through select event

1. exposted the selected dataItem through the itemSelect event through the e.dataItem property.  You can pass whatever data you want through the object you initially binded it through.
2. Made the contextmenu event on the document configurable through the event property.
Made close on click configurable through options. 

Also added a forceClose method which is hide the element no matter the configuration of the control.  I needed this as b/c of the mouseenter the context menu would stay open after I opened a modal kendo dialog from a context menu click.
Merge pull request #6 from jlipford/master

Added some positioning functionality.  Added default contextmenu stylesheet