Get positions of subsequences

[MitraDarja]

In order to analyze the coverage of the subsequences over a sequence, it is helpful to know their positions. There are two ways to do so:
a) Write a second function to every function returning the positions instead of the subsequences.
b) Write one function, getting the sequence and the subsequences and align them in order to get the positions.

The drawback of b) is that it takes more time to compute because the initial function needs to be called and then an alignment is applied, but its advantage is that it is only one function to implement, which then should work with every method.

For now, I think b) is the easier option. Should it be necessary to get the positions in a more efficient way, a) can still be implemented.