minor, provide resz() (similar to crea()) to resize an rbm

We remap the old (still active) rbm map to a MAP_PRIVATE mapping, then
ftruncate() the whole file to meet the new size criteria (MAP_SHARED),
then copy from the private to the shared map, and deactivate the private
mapping.

If there's new neurons (new size > old size) the new neurons will be
initialised with the same wobbling that created the old network.

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, refactor crea() routine in terms of pump() and resz()

Signed-off-by: Sebastian Freundt <hroptatyr@fresse.org>
fix, PEBKAC, use proper noise for the initialisation of w in resz()

Signed-off-by: Sebastian Freundt <hroptatyr@fresse.org>
minor, warn about populating vectors too large to go into the network

Signed-off-by: Sebastian Freundt <hroptatyr@fresse.org>
minor, read dimensions for initialisation and resizing from --dimen|-d

Signed-off-by: Sebastian Freundt <hroptatyr@fresse.org>
Merge branch 'feat/crea-resz'

* feat/crea-resz:
  minor, read dimensions for initialisation and resizing from --dimen|-d
  minor, warn about populating vectors too large to go into the network
  fix, PEBKAC, use proper noise for the initialisation of w in resz()
  minor, refactor crea() routine in terms of pump() and resz()
  minor, provide resz() (similar to crea()) to resize an rbm