Add selection tool

[TurtleMeds]

Is your feature request related to a problem? Please describe. A clear and concise description of what the problem is. I'm always frustrated when you create something really good, but it is in the wrong place.

Describe the solution you'd like A clear and concise description of what you want to happen. Add a new set of tools (rectangle select and free select/lasso tool) that allow you to:

1. Only draw inside the selection
2. Move the selection around
3. Delete everything in the selection

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature request here.

[tomdoeslinux]

Reopened under new leadership.