ANNOUNCE: CFFI 2.0.3 released

First official (non-beta) release of CFFI 2.0.
Repository: https://github.com/apnadkarni/tcl-cffi
Docs: https://cffi.magicsplat.com/
Downloads: https://sourceforge.net/projects/magicsplat/files/cffi
CFFI is a Foreign Function Interface extension for Tcl 8.6 and 9.
## Changes in v2.0
### Platform and backends
- Support for Tcl 9
- The `dyncall` backend now requires dyncall 1.4 and adds support for
   callbacks, variable arguments and passing of structs by value.
### Type declarations and annotations
- New class `Interface` for modeling COM objects.
- New class `Union` to support C unions.
- New base type `uuid`.
- Array type declarations can now use aliases as the base type.
- New `type` subcommands `tobinary` and `frombinary` to construct or
   deconstruct a binary string for any type declaration.
- The `nullifempty` annotation may also be applied for types `bytes`,
   `chars` and `unichars`.
- The `nullifempty` annotation may be used for optional `out` parameters
   to indicate they are optional.
- Added `saveerrors` annotation to save errno and Win32 error values and
   the `savederrors` command to retrieve them.
- New `discard` annotation to discard the result of a function call.
- New annotation `multisz` to support MULTI_SZ strings on Windows.
### Memory management
- New `memory` subcommands `towinstring`, `fromwinstring`, `tounistring`
   and `fromunistring`.
- New command `memory arena` for stack-like memory allocation at script
   level.
### Structs
- New option `-pack` for `Struct` to control alignment and padding.
- Added method `size` for structs and unions.
- Allow last field in a struct to be a variable size array.
### Enums
- Integer values for enum types that are bitmasks are no longer
   automatically mapped to list of enum members. Note enum members are
   still implicitly converted to integer values. *Incompatible change*
- New `enum` subcommand `alias` to couple an enum definition as an alias.
- New `enum` subcommand `names` to return names of enum members.
### Pointers
- `pointer castable` can now take multiple arguments.
- Pointer definitions within a struct or union have an implicit
`unsafe` annotation.
### Function definitions
- New syntax for comments within `functions` and `stdcalls` definitions.
- Output struct parameters can be passed as undefined variables.
- Annotation `retval` can be applied to parameters to `void` functions.
- Added option `-ignoremissing` to `Wrapper` methods `functions` and
   `stdcalls` to not raise error in case of missing shared library
   functions.
- Lengths of variable size array parameters can be passed through
   `byref` or `inout` parameters.
- On error exceptions, the `errorCode` variable now includes the numeric
   error code when one of the error handling annotations is present.
### Miscellaneous
- Enhanced `help` command.
- Built-in aliases are now loaded in the `::cffi::c` namespace and
   implicitly included in the search path.
- Various [bug fixes](https://github.com/apnadkarni/tcl-cffi/milestone/13?closed=1).