Export meshed microstructure to Abaqus

[CsatiZoltan]

Create an Abaqus class with the following desired capabilities:

• do not rely on the Salome API so that it can be factored out later to a standalone module (see also Rewrite the Abaqus module #28)
• additional functionalities required for running an Abaqus simulation (materials, section definitions, etc).
  This might seem unimportant at first sight (why would one do it, when they can be set from within Abaqus?), however, setting a different material property for each grain in a microstructure is tedious.

Also, create a script that shows the use of these.