Worked on the pull request section.
Fix broken link.
Fix typo.
Incorporate review changes from Chris
Fix a code example indent to match the 4-char spec
Shorten contributor license para per Chris's idea
Expanded ways to contribute section, added grant acknowledgments.
Fix TOC ordering
Added more coding conventions stuff and removed the "work in progress" comments.
Minor tweaks

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Move Acknowledgments section from CONTRIBUTING.md to README.md (thanks, Chris).
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Merge branch 'more-contributing-md-work' of https://github.com/simbody/simbody
Merge branch 'master' of https://github.com/simbody/simbody
Fix the easy things suggested by Chris, Tom, and Jason (typos, rephrasing, etc.).
Add TOC for coding conventions.
Fix messy tags.
Moved some things around a little.
Typo; thanks, Jason.
Merge pull request #287 from simbody/more-contributing-md-work

Final mods for initial CONTRIBUTING.md
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