build is a magic variable that acts similarly to subdirs, but specifies
files to build instead of subdirs. Using files provides a few advantages:
files can be named something more appropriate for the project than
"Blueprints", whatever you want instead of Blueprints, and multiple
Blueprints files can exist in the same directory.
A new variable is used instead of putting filenames into subdirs to avoid
unexpected behavior when a glob matches both files and directories.
subdirs= and build= entries that don't match any directories or files
are now reported as errors.
Change-Id: Id329504ace251eab4ccea1081a3c8665a4c52f5a
Make integrating with go tools easier by putting the blueprint package
files in the top level directory of the git project instead of in a
subdirectory called blueprint.
Change-Id: I35c144c5fe7ddf34e478d0c47c50b2f6c92c2a03
