s/catalogs/catalog/ in package-loader
add more text around local package init failure

text is the same used pre-packaging
make references to packageloader consistent
fix weird constraint solver bug
remove unnecessary whitespace from error
avoid terrible error

there was already a better error hidden!
Never add two sourceMappingURL notes to a file

(eg, when roundtripping through JsImage.readFromDisk)

Pre-0.9.0 this just means excessive rebuilds; on the packaging branch,
this means excessive version number bumps!
jsToLoad[i].source should be a string
trailing comma
clarify publish-release --from-checkout message
Restore --get-ready to its old meaning

It now builds all accessible local packages (as well as ensuring any
packages mentioned in your current app are downloaded)