ENH proj, now construct_dig_points

Went from add_dig_points to construct_dig_points. Avoids in-place
operation.
Expose layout param and expand use case for plot_projs_topomap
ADD support for kit epochs file
FIX indexing
ADD test epochs file with an event file
ADD test for epochs
ENH reshape data without copying
ENH massive overhaul to kit module
ENH memory efficiency
FIX gui
ENH cleanup