Better zoom functions

[Lebostein]

1. Zooming in to the point where the mouse cursor is
2. Rectangle zoom (that is a basic feature in ALL graphic programs in know)

At the moment the workflow is awfull. You have to switch between zooming and panning. With the first point above you can work with zoom (mouse wheel) only.

[Víctor Paredes]

I think the zoom is always related to the center of the current view.
You can go to the preferences and check "Zoom with drag box".

There are several ways to zoom and pan:
- Using the tools
- Using the Mouse wheel to zoom
- Using Dragging Right Click to Pan / Shift + Dragging Right Click to Zoom
- Using Space + Dragging to Pan / Shift + Space + Dragging to Zoom
- Ctrl + Alt + 9 to Zoom in / Ctrl + Alt + 8 to Zoom out

Also, there are shortcuts for fast zooming:
- Home resets the view
- Escape zooms over the selected layer content