Update devtool-build.md
details about switching release/branch cleared up a bit.
Merge pull request #760 from cloudedge/master

attempt to fix node_role data not being shown
Fix busted snapshot view, and update how we order roles in it.
Show grid if we have nodes or roles.
some syntax errors and formatting fixups
Add daemons as a required Gem dependency.
Merge pull request #763 from newgoliath/patch-3

+2 docs only
Merge pull request #764 from VictorLowther/pull-req-master-5efe77cdbed7029fcfd93b335eea0c50714e837e

+2
Merge pull request #762 from newgoliath/patch-2

+2 Docs
Merge pull request #761 from newgoliath/patch-1

+2 docs
make layercake colors mean something
add docs