v3.0.0 release.

[mshima]

• Conflicter is an environment feature now.
  • Removed first come, first serve restriction when using new api.
  • Remove not required apis.
  • Don't regenerate a file when identical (by default).
  • Logs and prompts are queued to a grouped-queue for out of order processing and optimized disc access.
    Every log is printed before going to next prompt.
  • Implement .yo-resolve file for pre-defined actions (skip, force).
  • Added transform and environment:conflicts priorities for new transform api and backward compatibility.
• Integrate and improve commit logic.
  • Conflicts checker are executed in parallel and completed out of order. Prompts don't block the entire process.
  • Add api for custom commit process.
• Integrated node package manager install execution.
  • Detects package.json in the root of the environment dir.
  • Detects the preferred package manager.
  • Executes package manager install in case of package.json have changed.
• Local generator repository.
  • Migrated to pacote and arborist.
  • Convert to async most of the api, due to no sync alternative.
• Singleton generators
  • Allow a generator to define a uniqueBy property, so it will be unique for the Environment.
• Experimental standalone cli.
• Drop callbacks and migrate to Promises.

Old generator apis takes precedence.
Improved workflow requires yeoman-generator >= 5.0.0.