Update manuscript: summary section

[egouldo]

• Take the first paragraph of the summary section and insert it in the current 'statement of need' section first paragraph, before the word moreover (and tie it in)
• take the third paragraph of the summary section and insert it into paragraph 2 of the 'statement of need' after the phrase "computationally reproduce our analysis"
• get rid of the rest of the summary section
• rename the statement of needs section 'introduction'