Reorganize paperspec commands and pin dependency versions (#2)

Reviewed-on: #2

spec/11-corrections.md

@@ -67,7 +67,7 @@ A correction is refused, naming the rule ([22](22-conformance.md)), when:
 11. the result breaks a rule of [3](03-nodes.md).
 
 The gate needs only the document's current state, so a tool can run it on a proposal before applying anything, and get back the record the correction would append or the rule it breaks.
-`tools/validate.py --correction` does this against a package.
+`paperspec validate --correction` does this against a package.
 
 Digits are characters of General Category Nd in the plain projection.
 A package's corrections are also checked as a whole: indexes run from 1 without gaps, each `id` derives from its record, `rev` equals their number, every retired ID is in `ids.jsonl`, and the last correction of each leaf ends at its current `node_hash`.