1.0/last updates tuesday sections

[becker33]

Final minor fixes from testing on both potential AMIs

[alalazo]

Instead of:

we can show the available scopes using:

$ spack config scopes
command_line             
env:/home/spack/stacks   
user                     
site                     
system                   
defaults                 
defaults:linux           
defaults:base            
_builtin                 

and maybe refer to include.yaml docs for further customization.

[alalazo]

I quickly checked the configuration tutorial, and it LGTM. If there's time, I wonder if we should introduce prefer: and require: and skip the soft preferences which are the lowest priority

[alalazo]

(nitpick, feel free to close without modifications if it seems pedantic) Changes to this file looks good. A minor point is in this wording:

Note the identifier clang_gfortran is not itself a spec (you don’t version it). You reference it in other specs. 

I'd rather say something like:

Toolchains are not specs, so they don't have versions or variants, but are referenced only by their names, in this case by `clang_gfortran`.