v2.2.0 - yyyy-mm-dd

Changes affecting backward compatibility

-d:nimStrictDelete becomes the default. An index error is produced when the index passed to system.delete was out of bounds. Use -d:nimAuditDelete to mimic the old behavior for backwards compatibility.
The default user-agent in std/httpclient has been changed to Nim-httpclient/<version> instead of Nim httpclient/<version> which was incorrect according to the HTTP spec.
Methods now support implementations based on a VTable by using --experimental:vtables. Methods are then confined to be in the same module where their type has been defined.
With -d:nimPreviewNonVarDestructor, non-var destructors become the default.

Changed std/osfiles.copyFile to allow to specify bufferSize instead of a hardcoded one.
Changed std/osfiles.copyFile to use POSIX_FADV_SEQUENTIAL hints for kernel-level aggressive sequential read-aheads.
std/htmlparser has been moved to a nimble package, use nimble or atlas to install it.
Added newStringUninit to system, which creates a new string of length len like newString but with uninitialized content.
Added setLenUninit to system, which doesn't initalize slots when enlarging a sequence.
Added hasDefaultValue to std/typetraits to check if a type has a valid default value.
Added Viewport API for the JavaScript targets in the dom module.
Deprecates system.newSeqUninitialized, which is replaced by newSeqUninit.

noInit can be used in types and fields to disable member initializers in the C++ backend.
C++ custom constructors initializers see https://nim-lang.org/docs/manual_experimental.htm#constructor-initializer
member can be used to attach a procedure to a C++ type.
C++ constructor now reuses result instead creating this.

--nimcache using a relative path as the argument in a config file is now relative to the config file instead of the current directory.

koch now allows bootstrapping with -d:nimHasLibFFI, replacing the older option of building the compiler directly w/ the libffi nimble package in tow.