Update of schemas + fix some bugs

-Massive update of schemas + minor change in the call (from setup.py) -Some bugs:

in pop.py, now "gridSpacing" is also in the list of excluded elements
in conn.py, included "params['preSec'] = connParam.get('preSec')" in gapJunctions
in stim.py, now "Loc" with capital letter (for compatilibity with analogous def in connParams)
in network.py, "del" instead of 'delay' (is a parameter of Iclamp o Vclamp)
in network.py, remove "i" from the list (it comes from AlphaSynapse, but it is an assigned value in the mod)
package reference, about subConn -> fix some misinformation.

suny-downstate-medical-center / netpyne