Gaps added by reverse with BioSequence slices

[timbitz]

I stumbled across the following behavior which I wasn't expecting, I narrowed it down to a length dependent behavior from slices with reverse which I think might not be returning a copy as it should?

julia> using Bio.Seq

julia> seq = DNASequence("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
32nt DNA Sequence:
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

julia> reverse(seq[(length(seq)-9):length(seq)])
10nt DNA Sequence:
AAAAAAAAAA

julia> seq = DNASequence("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
33nt DNA Sequence:
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

julia> reverse(seq[(length(seq)-9):length(seq)])
10nt DNA Sequence:
A---------

julia> reverse(copy(seq[(length(seq)-9):length(seq)]))
10nt DNA Sequence:
AAAAAAAAAA

julia> Pkg.status()
 - Bio                           0.4.2

[bicycle1885]

Thank you. I'll take a look at it as soon as possible.