Add option to hide title bar

[mike-ward]

Add an option to hide the title bar. This can be accomplished by setting WindowStyle=None. However, there's a bug in Windows 10 where the top of the title bar frame still shows when setting the window style to None. So I'll also have to set ResizeMode=None when this option is selected.

This will also help with the issue of the inactive title bar being white.

[mike-ward]

Hiding the title bar had the weird side affect changing the internal size and making it hard to line up.

Implementing my own title bar allows me to make it smaller and the color remains fixed. This is what the original gadget did.

The one side effect I'm not going to work out in this release is that resizing can only be done by using the gripper control in the bottom right corner.