ZS in no_db mode

[jmbenlloch]

In ZS mode the number of sensors can be different for each event. The current hdf5 file structure does not allow for that. The size of the array will be fixed by the amount of sensors in the first event. If any later event has more than that, there will be an error:

[2018-07-10 16:28:32.192] [DB] [info] Sensors mapping read from NEWDB in neutrinos1.ific.uv.es
nsipms: 176
[2018-07-10 16:28:32.210] [rawdata] [info] Event number: 2
nsipms: 154
[2018-07-10 16:28:32.271] [rawdata] [info] Event number: 3
nsipms: 164
[2018-07-10 16:28:32.328] [rawdata] [info] Event number: 4
nsipms: 168
[2018-07-10 16:28:32.385] [rawdata] [info] Event number: 5
nsipms: 178
HDF5-DIAG: Error detected in HDF5 (1.8.18) thread 139687871723328:
  #000: H5D.c line 999 in H5Dset_extent(): unable to set extend dataset
    major: Dataset
    minor: Unable to initialize object
  #001: H5Dint.c line 2291 in H5D__set_extent(): unable to modify size of dataspace
    major: Dataset
    minor: Unable to initialize object
  #002: H5S.c line 1870 in H5S_set_extent(): dimension cannot exceed the existing maximal size (new: 178 max: 176)
    major: Dataspace
    minor: Bad value
HDF5-DIAG: Error detected in HDF5 (1.8.18) thread 139687871723328:
  #000: H5Dio.c line 266 in H5Dwrite(): file selection+offset not within extent
    major: Dataspace
    minor: Out of range
[2018-07-10 16:28:32.434] [rawdata] [info] Event number: 6
nsipms: 153

Totally related to #2.