Merge branch 'master' into dev-CC-Docker

* master:
  tweaked polymer trace for coarse units
  provide some feedback for users in canvas app
  wip, carbohydrates and branched entity
  support cif files with only safeFrames
  wip, carbohydrate related schema additions
  tweaks to carbohydrate handling for remediated structures (and fixes)
  added alt_id to element label
  package update
  optimized idField creation when creating gaussian density field
  wip, gaussian surface picking / coloring
  fixed normal dir in normal calculation
  added molecule-type color scheme
  ModelServer: custom property providers defined by config file
  ModelServer: support BinaryCIF "encoding providers" from source file
  cleanup and package updates
  added sequence-id and secondary-structure color schemes
  added matplotlib derived and other color scales
  tweaks for coarse/backbone only models
  tweaked point filled circle shader