Cleanup and Refactoring for 1.0
- class AgentSet:
  - constructor: same for all agents sets
  - setDefault: install class variable and value for any agentSets
  - own: install class variables for unique agentSet variables by modeler
  - ownVariables: keep an array of names of own variables for UI/FireBase
  - breeds, or agentSet subsets, available for all agentset instances
  - add/remove: breed aware
- Model:
  - create ABM.world, Patches: use world for creating patches set
  - globals: a list of names of variables created in setup(), for UI/FireBase
  - add patchBreeds as well as agent/link breeds
- Sprites:
  - Keep index of all created sprites to avoid duplicates
  - agents.sprite and agents Agent::sprite default sprite: used if present
  - agents.setDefaultSprite: install Agent::sprite shared by all agents
  - agent.setSprite(sprite) set a unique sprite for an agent, setting color, shape, size too
  - avoid dataURL cross origin problem when enlarging sheets
- Util:
  - randomMapColor: limit r,g,b to a set of values rather than all ints in 0..255
  - randomBrightColor: randomMapColor w/ oneOf [0,127,255] for r,g,b
- Create source map for agentscript.coffee