#61 Introduce a general @FiniteStrainStrategy keyword. Deprecate definition of the finite strain strategies in the interfaces.

[Helfer Thomas]

Introduce a general @FiniteStrainStrategy keyword.
Deprecate definition of the finite strain strategies in the interfaces.

[Helfer Thomas]

The StrainMeasure keyword has been introduced. This keyword is
followed by the name of a strain measure:

• Linearised (small strain behaviour)
• Green-Lagrange
• Hencky

The stress tensor computed by the behaviour is interpreted as the dual
of the strain measure chosen.

The definition of the finite strain strategies in interfaces has not
been deprecated, as this allows to define general purpose behaviours
available in various "flavours".

[Helfer Thomas]

mfront-query now have two related queries:

• --is-strain-measured-defined: returns true if a strain measure has been defined;
• --strain-measure: returns the name of the strain measure, if any.

Depending of the fact that strain measure is handled by the solver or by MFront, the getUMATBehaviourKinematic method of the ExternalLibraryManager class may return the following values:

• 0: undefined kinematic
• 1: standard small strain behaviour kinematic
• 2: cohesive zone model kinematic
• 3: standard finite strain kinematic (F-Cauchy)
• 4: ptest finite strain kinematic (eto-pk1)
• 5: Green-Lagrange strain
• 6: Miehe Apel Lambrecht logarithmic strain framework