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!
DOC remplace iff by if and only if
Merge pull request #1315 from sciunto/ffi

DOC remplace iff by if and only if
try to format properly a function in examples of RectTool
deleted ">>>" in body of print_the_rect function
Clip to min and max range of input image, add missing clip parameter to other functions
Introduce parameter to keep range of values
Fix keep_range and add test cases
Create helper function for image conversion
Make sure 1x1 images are 2-D
Remove test for invalid shape
Rename keep_range to preserve_range, fix test cases
Remove __init__.py from tests folder, remove unnecessary load of test image
... added in indented code
Fix matching test cases
Fix novice module with new dtype behavior
Use in-place operation for clipping
Add more description to doc string of helper function