Add handling for Modulo 128 AX.25 frames

[loredous]

Is your feature request related to a problem? Please describe.
Currently the code only handles Modulo 8 frames. To support the full AX.25 spec, it should also handle Modulo 128 frames.

Describe the solution you'd like
The code should be able to auto-detect the modulo level of a frame during decode. During creation, it should utilize the modulo argument to determine how it should handle the frame.