Minor typos and grammar fixes in paper

[raphaelreinauer]

Per the JOSS review checklist:

Quality of writing: Is the paper well written (i.e., it does not require editing for structure, language, or writing quality)?

There are some minor grammar issues/typos in the paper:

Summary section:

• "scientific package" → "scientific packages"

Statement of Need section:

• "addressed" → "addresses"
• "complimented" → "complemented"
• "Tranforms" → "Transforms"

Part of this JOSS review.