Merge branch 'maint'

* maint:
  Do driver_deq in worker threads instead of async_ready
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'

* maint:
  Fix a bug in the Erlang scanner
Merge branch 'maint'

* maint:
  Document erl_parse:abstract/2
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'
Merge branch 'maint'
[sasl] Quote path to program run with open_port({spawn,...

This is to allow space in the path.
Quote path to erl executable in slave to allow space in path
[test_server] Quote path to erl executable when starting slave nodes

This is to allow space in path.
Merge branch 'maint'
Update primary bootstrap
Merge remote branch 'upstream/maint'
Merge branch 'maint'