* Fix NullablePointer type constraint check being omitted in FFI declarations
* Change to Steed's model of subtyping
* Fix memory corruption with Array.chop and String.chop
* Improve error message for match on structs
* RFC 68: Mandatory FFI declarations
* Change return type of String.add to String iso^
* Improve error message on destructuring of non-tuple types
* Use built-in offset argument to cpointer
* Add IsPrime checker to math package
* Fix compiler crash related to type parameter references
* Fix literal inference through partial function
* Fix partial FFI declarations ignoring partial annotation
* Fix symbol table patching for overriding default methods
* Fix tuple related compiler segfaults
* Create a standalone libponyc on Linux
