another makeover of loadparm to support new stuff in swat and

another makeover of loadparm to support new stuff in swat and
testparm.

In particular I added:

- ability to optionally save default values of all parameters when
  calling lp_load(). This can then be used to save only non-default
  parameters in lp_dump(). This makes the saved smb.conf (and viewed
  parameters in testparm) much shorter

- ability to not load ipc share in lp_load()

- separators in parm_table[] so parameters can be grouped logically.

- flag to mark parameters that are local but which should be also
  viewed as global as far as parameters editing is concerned
(This used to be commit f9af35da26e58fb0b644b5f0169f1c212230047a)