pyelmer v0.2.0

• Merged pull request from Anil Kunwar:
  • execute.py: run_elmerf90
  • simulations.yml: "2D transient"
  • solvers.yml: "ThermoElectricSolver"
• Improved behavior of 'import pyelmer'
• Summarized gmsh_objects and gmsh_utils to single gmsh module
• Write equation, force, initial condition, material, solver name in body / equation in sif
• renamed surf_id to geo_id in Body class
• Intoduced proper versioning numbering using versioneer
• Codestyle: black
• Bugfixes in gmsh Shape, Model
• Cleanup and minor bugfixes