Update commiters

better alignment
Layer mgmt - Adding some methods

Preparing some methods to manage (delete / add) layers
Layer QUndo framework - Adding command-related files
Layers model - hardenning layermodel elem selection
Layer model - Adding layers on mainwindow

layer initialization is still a little bit buggy, but I might wait for
@yjacolin work on the interface. Need to init the fields of the Layer
class (or it leads to several unothaurized memory access).

But clicking on "add layer" is now working (well, almost ...)
layer insertion - fixing segfault

Imitating what is done when parsing a mapfile in mapserver's code,
instead of using the provided API to insert a layerObj.