Bug fixes and updates for release 2020.1.2

• Wflow_sbm and wflow_hbv
  • Improved kinematic wave solution when iterating: now using states at sub-timestep. This change affects the simulated discharge (timing and peaks) quite a bit (compared to previous versions)
  • Changed self.reallength to self.xl and self.yl for cell area calculation, this is more precise for lat lon models
  • Small fixes for wflow_hbv (exporting riverwidth map and "pcr" (PCRaster) missing for accucapacitystate function (pcr.accucapacitystate))
• Fixes and updates for wflow_topoflex
• Fix glacier melt issue (could contain missing values)
• Fix issue with Numba versions > 0.48 (numba.errors moved to numba.core.errors)