Spawn new tasks onto the primary scheduler by default. #3760
Add at_exit function #4450
core: Add private global data interface. #3915
Add `finally` method for deferred execution
drop is_not_empty from TreeSet/TreeMap
std: un-ignore strptime test; fix bug introduced by 1a226f instead.
Handle divide by zero in constant evaluator
Merge pull request #4586 from thestinger/treemap

drop is_not_empty from TreeSet/TreeMap
Add is_mutbl field to arg
Parse `mut` in arguments
Add is_mutbl field to def_arg
Implement `mut` in arguments
syntax: Allow closure args to be mutable
syntax: Pretty-print `mut` qualifiers on args
testsuite: Add tests for mutable function arguments
doc: Document mutable function arguments
core: Rename to_mut and from_mut to cast_to_mut and cast_from_mut
doc: Document pattern matching on vectors
Merge pull request #4588 from sanxiyn/doc-mut-arg

doc: Document mutable function arguments
Merge pull request #4596 from Trinick/tomutrename

core: Rename to_mut and from_mut to cast_to_mut and cast_from_mut