Add comments to help implementors.
Add comments to help implementors.

svn path=/trunk/kdepim/; revision=334791

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi