Remove parallel from arviz.utils.full (fixes #904)

[nitishp25]

Removed parallel arguement from numba @conditional_jit in arviz.utils.full

fixes #904

[nitishp25]

@OriolAbril Please review :)

[OriolAbril]

Hi, you should rebase your remove-parallel-from-full branch. If you have followed the steps in the contributing guide you will only need these two lines from step 5:

$ git fetch upstream
$ git rebase upstream/master

Otherwise you will have to add the upstream remote as explained in step 2:

$ git remote add upstream git@github.com:arviz-devs/arviz.git

[nitishp25]

@OriolAbril I had added upstream earlier and just fetched and rebased it but there appears to be no change.
I also did that before pushing changes to my own repo.

[nitishp25]

Please review now @OriolAbril