Expansion of numeric literals (decimal, binary, hex) and addition of environment configuration features by introducing a config file

[snowykr]

Expansion of numeric literals (decimal, binary, hex) and addition of environment configuration features by introducing a config file

[snowykr]

Internally normalize everything to int values.

It is already implemented to perform calculations using a 16-bit width to comply with the actual SN/X architecture hardware specifications.
Therefore, I only need to provide options to configure the display settings.

[snowykr]

#8 also has to use this config file.
example: word_size_bytes, data_base_addr, allow_negative_dw, ...

The original C-based snxasm assembler does not support the DW directive, and this project aims to stay compatible with that behavior. For this reason, I decided not to add DW support here.

[snowykr]

I decided not to add config file for saving options.
I am distributing this as a command-line package, and I think that persistently saving options might actually inconvenience the user in some case.

Therefore, I decided to proceed by adding command-line options such as --output-format.