Reorganize paperspec commands and pin dependency versions (#2)

Reviewed-on: #2

fixtures/README.md

@@ -35,7 +35,7 @@ A conforming reader accepts each one and recomputes every hash it contains.
 ## Records
 
 `records/` holds a valid example of every other format that is a JSON file of its own.
-Three formats have their example elsewhere: the stage requirements (`scienting-stages/1`) and the stamp rules (`scienting-stamps/1`) are in [registry/](../registry/README.md), and a bundle (`scienting-bundle/1`) is a SQLite file that `tools/load.py --bundle` builds from the packages.
+Three formats have their example elsewhere: the stage requirements (`scienting-stages/1`) and the stamp rules (`scienting-stamps/1`) are in [registry/](../registry/README.md), and a bundle (`scienting-bundle/1`) is a SQLite file that `paperspec load --bundle` builds from the packages.
 Each record is a single file, or a folder where a format needs several files.
 
 | Files | What they are for |
@@ -109,4 +109,4 @@ Use them for nothing else.
 ## Sources
 
 `src/` holds the hand-written descriptions of the three main documents, as first read; see [src/README.md](src/README.md).
-Everything else here is generated by `python3 tools/build.py`, so change the sources or the builder, never the generated files.
+Everything else here is generated by `paperspec build`, so change the sources or the builder, never the generated files.