Fix #1518: Don't assume aggregates in dev doc
Fix #1518: Don't assume aggregates in dev doc

Packaging the library is sufficient to build both the compiler and the
library, since compiling the library depends on the compiler. This
does not build the tools, but the build itself does. Therefore, this
seems like a reasonable introduction to the beginning developer.

ummels/scala-js,SebsLittleHelpers/scala-js,lrytz/scala-js,jmnarloch/scala-js,mdedetrich/scala-js,Vp3n/scala-js,spaced/scala-js,renyaoxiang/scala-js,jmnarloch/scala-js,scala-js/scala-js,doron123/scala-js,japgolly/scala-js,andreaTP/scala-js,gzm0/scala-js,gzm0/scala-js,doron123/scala-js,spaced/scala-js,yawnt/scala-js,xuwei-k/scala-js,renyaoxiang/scala-js,CapeSepias/scala-js,sjrd/scala-js,xuwei-k/scala-js,xuwei-k/scala-js,sjrd/scala-js,matthughes/scala-js,andreaTP/scala-js,jasonchaffee/scala-js,scala-js/scala-js,nicolasstucki/scala-js,renyaoxiang/scala-js,Vp3n/scala-js,yawnt/scala-js,colinrgodsey/scala-js,matthughes/scala-js,andreaTP/scala-js,lrytz/scala-js,spaced/scala-js,Vp3n/scala-js,nicolasstucki/scala-js,sjrd/scala-js,doron123/scala-js,ummels/scala-js,matthughes/scala-js,jasonchaffee/scala-js,scala-js/scala-js,ummels/scala-js,mdedetrich/scala-js,yawnt/scala-js,CapeSepias/scala-js,japgolly/scala-js,SebsLittleHelpers/scala-js,jmnarloch/scala-js,mdedetrich/scala-js,colinrgodsey/scala-js,CapeSepias/scala-js,colinrgodsey/scala-js,japgolly/scala-js,jasonchaffee/scala-js