RC2 1.0 release candidate

[jrincayc]

This fixes and clarifies some details (Thanks Elizabeth Cogliati for pointing out the first four).

• Mentions #t when discussing true for first time
• Explain how to use () in program instead of just stating it is not a legal expression.
• fixes missing comma in list
• atom was not defined, so say simple value instead
• pico doesn't have libraries, so removing mention in summary
• None of the R7RS small's SFRI's are actually used in Pico, so remove list.

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This discussion was created from the release RC2 1.0 release candidate.