Definition of an ElementProperties

An set of element properties (ElementProperties object) is defined with the following lines:

prp = ElementProperties(typeEl)
prp.put(param1, valeur1)
prp.depend(param1, fct1, Lock1)) # optional
prp.put(param2, valeur2)
prp.depend(param2, fct2, Lock2)  # optional
...

where

`typeEl`	type of finite element (for example `Volume2DElement`) - see Volume element
`param1`, `param2`	code of the propriety relative to the element (for exéample `MATERIAL`) - see Eléments finis
`valeur1`, `valeur2`	“value” of the corresponding property
`fct1`, `fct2`	function which characterizes the dependency of the property (optional: no `fct` if no dependency)
`Lock`	Lock which defines the dependency variable of the property (compulsory if there is a dependency)