Delivery meter: 4 days to finish proposed tasks

Created icons for the 2D and 3D windows, added them on the forms. Will work at adding them functionalities like zooming, rotating.

The next steps to be made on development:

1. Implement at 2D: zooming, grid lines, panning,
2. Implement at 2D: tool for drawing a rectangle, code for drawing a rectangle,
3. Snapping at 2D,
3. Add at 3D: panning, zooming, change drawing to wireframe/solid,
4. Code cleanup, prepare some application architecture document with explanations,
5. Make functional the following use case: the application starts in 3D mode (code done), a surface is selected and the sketcher launched knowing the coordinates of the selections (code done), draw a rectangle with the rectangle tool(code to be made in the next days), change back to 3D and show the 2D rectangle (code made, needs improvements)

Will insist on finishing these functionalities over this weekend and have something functional until Monday night, that is March 31st. So 4 more days to finish these tasks. To motivate myself I will make a delivery meter posted daily on the blog: 4 more days until deadline.