Julia 1.0 support: new iterator interface

[carstenbauer]

This PR adds support for the new iterator interface to make the package work in Julia 1.0.

[carstenbauer]

I suggest tagging a new release after this has been merged to make the package function in 1.0.

[rahulkp220]

Thanks for the PR @crstnbr , Can you also update the REQUIRE file too?

[carstenbauer]

What update do you have in mind?

Currently it contains julia 0.6 which should include all Julia versions >= 0.6, which seems fine to me (Note that I didn't remove the old iterator interface implementation).

[rahulkp220]

I was thinking to upgrade it to Julia 0.7, which would then take it to the next stage easily with 1.0. I guess the tests were already fixed for deprecations in an earlier PR

[carstenbauer]

So you want to drop 0.6 support? If so, I should delete the old iterator interface (and version based branch), which is only needed for julia < 0.7.

[rahulkp220]

Hmm, let's leave it there. I wished to go post 0.7, but I guess, its okay for some time to have 0.6 supported. I agree with your initial comment on keeping it at 0.6.

Also, I have sent an invite for you to become a collaborator :)

[carstenbauer]

Ok, thanks! I'll finish this up (will add some iterator test).

[codecov-io]

Codecov Report

Merging #16 into master will increase coverage by 5.12%. The diff coverage is 100%.

@@           Coverage Diff            @@
##           master    #16      +/-   ##
========================================
+ Coverage   94.87%   100%   +5.12%     
========================================
  Files           1      1              
  Lines          78     51      -27     
========================================
- Hits           74     51      -23     
+ Misses          4      0       -4

Impacted Files	Coverage Δ
src/PeriodicTable.jl	100% <100%> (+5.12%)	:arrow_up:

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[carstenbauer]

v1.0 CI failures are due to Pkg not defined. This will be a reason to drop 0.6 at some point. I'll rebase and merge.

[rahulkp220]

Yeah, I guess a move to 0.7 will be inevitable very soon.

[carstenbauer]

Could you tag a new release such that 1.0 users will be able to use the package?

[rahulkp220]

For any new release, just draft a new one and attobot will take care of the rest :) Anyways, you can track it here https://github.com/JuliaLang/METADATA.jl/pull/17855