[DEV] v2.8.0: Extended syntax & typing fixes

[MatrixEditor]

This pull request tracks the status while transitioning to the v2.8.0 release

As mentioned in #53, having a type-checker compliant class definition would increase the usability of this library, changes made here introduce a new syntax, named "extended syntax". It allows specifying fields alongside their Python type without breaking the core concept of caterpillar.

The newly introduced type aliases apply a specific naming scheme and always end with _t, so they can be distinguished from normal struct types.

from caterpillar.types import uint32_t # new module
from caterpillar.shortcuts import f # extended syntax field specifier
from caterpillar.py import struct, uint32 # struct types

@struct
class Format:
    # Annotating fields is the same as before. This time, is is important to note that we can 
    # either use the type directly or specify it manually
    value: uint32_t
    # manual definition
    value: f[int, uint32] # NOTE: no '_t' here as we have to use the struct here

# packing and unpacking is still the same...

TBD

Additions

• Invisible field specifier that can be used to "hide" struct fields in the constructor (when using a type checker)
• struct_factory.mixin and bitfield_factory.mixin both provide default function wrappers for packing and unpacking data as well as typing fixes for operating on types directly.
• Add new parentctx context path
• Dynamic endian is now used by default (i. e. can be changed via order= in pack() or unpack())
• Add new generic Timestatmp class

Other changes

• Merge all stub files with their corresponding Python files. All typing is now inline.
• A number of new test cases
• padding struct now has its own dedicated class
• sizeof() now always returns an integer
• IntFlag support for Enum structs (IntFlag support & global default endianess #56)

Fixes #54