Simput Model missing some LW_Test.yaml keys

[DrewLazzeriKitware]

We fail to read in all of the keys from the Little Washita example. These keys are missing, and are hardcoded in:

simulation-modeler/server/SimulationManager.py

Lines 8 to 34 in 0df97b8

	defaults = {
	#
	# These require reading nested keys
	#
	"Cycle.constant.alltime.Length": 1,
	"Cycle.Names": "constant",
	"Cycle.constant.Names": "alltime",
	"Cycle.constant.Repeat": -1,
	"Patch.x_lower.BCPressure.alltime.Value": 0,
	"Patch.x_upper.BCPressure.alltime.Value": 0,
	"Patch.y_lower.BCPressure.alltime.Value": 0,
	"Patch.y_upper.BCPressure.alltime.Value": 0,
	"Patch.z_lower.BCPressure.alltime.Value": 0,
	"Patch.z_upper.BCPressure.alltime.Value": 0,
	"PhaseSources.water.Geom.domain.Value": 0,
	#
	# These require top level __value__ keys
	#
	"Gravity": 1.0,
	"FileVersion": 4,
	"KnownSolution": "NoKnownSolution",
	"Solver._value_": "Richards",
	#
	# These may be wrong in LW_Test.yaml. That key doesn't exist in pf-keys
	#
	"Solver.Linear.Preconditioner._value_": "PFMGOctree",
	}

[DrewLazzeriKitware]

This branch is some progress towards reading the nested keys, as well as some cleanup of the script: https://github.com/DrewLazzeriKitware/simulation-modeler/tree/support-nested-keys