Added a function to do bulk creation of output variables.
Merge branch 'master' into simpler-reporting
Merge branch 'master' into simpler-reporting
Added instructions on updating the C engine on the production server (issue https://github.com/NAVADMC/SpreadModel/issues/217).
None of the modules use RPT_group output variables anymore. Instead, the modules store 1D or 2D arrays of output variables when they want sub-categories or sub-sub-categories.
Removed the "1 level deep" versions of several functions for output variables.
Deleted the RPT_group output variable type and all code that used it.
is_null is now just a field lookup, not a function call.
Added constraint for #227
Added variables for adequate exposures broken down by cause.
Removed some useless output variables that get created just because of the loops over all possible contact types, control reasons, etc.
Merge branch 'master' into simpler-reporting

Conflicts:
	CEngine/modules/full_table_writer.c
Restored some changes accidentally overwritten in last merge.
JS to constrain the min / max values of population filters.  Closes #227
Constrained airborne 1km spread to .999.  Closes #191
Added fallback line in README for port forwarding.
Restyled "All Possible Interactions" to make it clear that it is separate.  Fixes #231
Checkboxes are now properly attached to labels and query the current DB state during construction.  #118
Removed the subelement argument that several of the output variable functions used to take.
Merge branch 'master' into simpler-reporting