add fields to the hem_app_runparams table

[Kathie Dionisio]

A few additional fields are needed in the runparams table, to be able to track all input parameters used when generating dose results, so that runs can be duplicated if necessary (and traced back to which parameters were used to generate results, so that dose results can be interpreted accurately). These input parameters are new to the HEM model. Fields to add to hem_app_runparams:

compmethod (takes value 1 or 2)
chemseed (integer)
houseseed (integer)
pucseed (integer)
pucoffset (integer)