scikit-image tutorial given at euroscipy 2013

creation of a Packages section
A few modifications following PR review by Gaël
Some quick modifications to the image processing chapter in the advanced
section.
scikit-image tutorial: some references to the online documentation
Add a small description to the packages section
fix typo
ENH: modernize the Mayavi chapter
WIP
Mayavi EM example
Source, filters and modules
Section on data animation
Add forgotten file
Interactive dialogs
Take in account @Emmanuelle's remarks
ENH: mayavi interactive dialog
Add a final exercise
fix typo

Conflicts:
	advanced/3d_plotting/index.rst
Add a final examples
Move into packages
Formatting issues in scikit-image