fax update for the campaign.

[mcfatelin]

New update of fax specifically for the use of the analysis campaign. The main changes are:

1. PMT gains and gain sigmas are now from PMT WG, which accommodate the condition in the first science run.
2. Change the s2_area_mean_top_fraction to the updated value in MC. See Issue#491
3. Corrected the PMT after pulse probability. Previous one was 100 times higher.
4. The time resolution of ion-residual PMT after pulse is added. Values are from JulienW
5. Also the uniformly time-distributed PMT after pulse was implemented. See summary note for more details of such type of PMT after pulses. Because it can happen very close to the primary hit, it is potentially a important responsible for peak finding/classification/clustering efficiency loss.

However this will not be the last update of fax during the analysis campaign. The foreseen update on fax would be the implementation of multi-PE PMT after pulse generation.

[JelleAalbers]

Diff looks good, simulated events look good