JOSS review: edits to paper.md

[nirum]

A few suggested edits in the paper.md file:

• First sentence of the second paragraph, change "for generic optimization problem" to "for generic optimization problems"
• "taylored" should be "tailored"
• Are the references missing for adaptive pattern search and SPSA?
• Add text mentioning that this is for zeroth-order (gradient free) optimization (issue #8)

[andim]

Thanks for catching the typos and thanks for your clarification question. I have updated the paper accordingly -- let me know what you think!

[nirum]

Looks good!