Active Cursor Tracking (#12)

[CardBreaker]

This adds an optional active cursor tracking feature as part of #12. Major changes:

• Adds an Options menu where you can toggle the feature.
• When enabled, cursor now actively follows the mouse.
• When enabled, left clicking places a note.
• When enabled, left click and hold changes the note size. Left release places the note. I wanted to add right click detection during this to cancel the note placement, but XAML doesn't let you detect multiple different mouse press/release events at the same time.
• When disabled, the old logic runs. I did not modify or fix the old behavior.
• Regardless of the active cursor tracking setting, right hold and scroll now affects the note size.
• Miscellaneous refactor to reduce unnecessary variables.

[Raymonf]

Overall looks good initially. Could you please move the settings to the Settings dialog?

[Raymonf]

I'll give this a test when I get the chance and fix up the formatting probably sometime tonight. Thanks!

[Raymonf]

Merged, thanks!