Change cursor based on tool selected

[garakmon]

This should resolve Issue #7 .

*This changes the cursor only over the editable part of the map.

[garakmon]

[garakmon]

Latest commit addresses #51 and #33 Adds:

• View Menu with keyboard shortcuts > Zoom In (+) / Zoom Out (-)
  • default scaling is 5/4 - 4/5
• Map ‘+’ cursor drag and move edit mode that can also be toggled with M key

Not implemented: scroll wheel zooming in drag mode (but keyboard shortcuts should be sufficient at least for now).

[garakmon]

Demo:

[huderlem]

The icons you're using seem jarring to me because their base coordinate is different. The pencil's is bottom-left, the bucket's is bottom-right, etc. I think this cursor style is easier to use:

[garakmon]

I did it the way I did just because I wanted the tools to work from the tip (like, the pencil shouldn't draw from the middle, etc.), but this is also a good solution.