[DEV] Custom operators

[MatrixEditor]

Version 2.0.1 adds support for user-defined operators and fixes an issue with the sizeof calculation of FormatFieldobjects.

Custom Operator (example)

from caterpillar.model import struct, sizeof
from caterpillar.fields import uint16, _infix_

# operator definition here (@_infix is also possible)
M = _infix_(lambda _s, count: _s[count * 2])

@struct 
class Format:
    values: uint16 /M/ 3