add Sachs, Taylor, BetaRule and Idiart schemes

[antoinecea]

No description provided.

[thelfer]

cmake fails as follows:

CMake Error at cmake/modules/behaviours.cmake:230 (add_custom_target):
  add_custom_target cannot create target
  "MericCailletaudSingleCrystalViscoPlasticity-md" because another target
  with the same name already exists.  The existing target is a custom target
  created in source directory
  "/home/th202608/codes/MFrontGallery/master/src/MFrontGallery/generic-behaviours/viscoplasticity".
  See documentation for policy CMP0002 for more details.
Call Stack (most recent call first):
  cmake/modules/behaviours.cmake:355 (generate_mfront_doc)
  generic-behaviours/homogenization/CMakeLists.txt:1 (mfront_behaviours_library)


CMake Error at cmake/modules/pandoc.cmake:67 (add_custom_target):
  add_custom_target cannot create target
  "MericCailletaudSingleCrystalViscoPlasticity-description-html" because
  another target with the same name already exists.  The existing target is a
  custom target created in source directory
  "/home/th202608/codes/MFrontGallery/master/src/MFrontGallery/generic-behaviours/viscoplasticity".
  See documentation for policy CMP0002 for more details.
Call Stack (most recent call first):
  cmake/modules/behaviours.cmake:232 (pandoc_html_base)
  cmake/modules/behaviours.cmake:355 (generate_mfront_doc)
  generic-behaviours/homogenization/CMakeLists.txt:1 (mfront_behaviours_library)

[thelfer]

There are many warnings about ignoring the returned value of the integration of behaviour variables. Would you correct this ?
Also, there are warnings about computeTangentOperator_ and smt...