Updated some paths after the Emacs configuration directory was moved
Some variables in my dotspacemacs were renamed in order to follow the
Spacemacs coding style with a ~//~ used for marking private variables,
and I prefixed their name with ~dotspacemacs-~ in order to avoid any
collision with other packages or configuration I write.
Added back M-« and M-» in order to fix the M-< and M-> shortcuts issue
with the bépo layout.