Added an example of use of CanvasTools.RectTool to allow generation of docs.
RectTool is used to write rectangles over an image (lena).
This example also can be useful for set_color explanation using both [RGB] and single value color setting
Added an example of use of CanvasTools.RectTool to allow generation of docs.

RectTool is used to write rectangles over an image (lena).
This example also can be useful for set_color explanation using both [RGB] and single value color setting

from previous commit indented code in examples is formatted properly.
Contributor file updated .... very nice to be part of this beatiful scikit!
try to format properly a function in examples of RectTool
deleted ">>>" in body of print_the_rect function
... added in indented code
Travis auto-build Doctest skipped to avoid window opening
removed numpy import and spaces
Merge pull request #1314 from SalvatoreScaramuzzino/RectTool_docs

Rect tool docs