Add configuration options for jpegoptim post-processor

[dylanschoenmakers]

Added configuration options (max, progressive) for the jpegoptim post-processor:

filter_sets:
        my_filter:
            post_processors:
                jpegoptim: { max: 65, progressive: false }

[lsmith77]

can you add a note to the docs and rebase on master?

[lsmith77]

BTW this PR seems to overlap with #720

[alexwilson]

Might make sense to delay this until after #720 is merged, then it can be rebased and the constructor conflicts can be resolved

[dylanschoenmakers]

Any chance this could be merged now with my latest changes? I've copied the constructor arguments from #720 to match.

[lsmith77]

so you think this PR now makes #720 obsolete?

[alexwilson]

I feel like the two are halves reaching towards the same goal, but with slightly different features and ultimately we should be okay to merge either in first.

If this is merged in first, then I'm happy to rebase #759 (a cleaned up version of #720) again against this today and resolve the constructor conflicts, which will then allow for that to be closed too.

[lsmith77]

ok .. lets go!

[alexwilson]

wooo!