Add realitime images reading from Kinnect.

I have created new subscriber/server that reads data published by Kinect and offer last read image as an service.
  - ImageReaderService.py
It means to create new service message.
  - srv/GetImage.srv
Moddify Folding process script to use the service.
Add support scripts for homography estimation and modified model maker.
Add tresholding test
Fixed error when the app crashes beacuse it selected only one grapsed point.
Moddification of the take_picture script to be able to grab images from Kinect or a file.
Nothing is without small errors
Back to the trees. White background sucks. Especially in not contrast scenes.
Create new homography for Kinect and update thresholding for green background.
I forget to change background from white to greenn in this script.
Add extra translation to homografy to get whole picture to the scene.
Green threshold modification.
It seems that towel folding works fine.
Merge branch 'dev', remote-tracking branch 'origin/master'