Automate the swapping process

[Aniq55]

Linking the keygen with encoder

Let KeyTuple= KT, so we have KT1, KT2, KT3, KT4.
For each we generate and store
[KT1, KT1_1, KT1_2, KT1_3, ...... KT1_N ]
and similarly for KT2, KT3 and KT4
We travel throught the lists one by one and swap the pixel values.
We do the same task while decoding but in reverse order.
This process is memory-intense but it will prevent stack-overflow which
would have occurred had we used recursion