add a global --quiet commandline option
move `relengapi.proxy` to `relengapi.lib.proxy`
move `relengapi.subcommands` to `relengapi.lib.subcommands`
move `relengapi.db` to `relengapi.lib.db`
Rename `relengapi_blueprints` to `relengapi.blueprints`

..but keep compatibility with the old name
include more notes on source of fiximports.py
distinguish fiximports modification from fiximports failure
use better messages in the test
Merge djmitche/build-relengapi:global-quiet (PR #110)
remove some redundant code calling iter_entry_points
Merge djmitche/build-relengapi:issue78 (PR #78)
Merge djmitche/build-relengapi:issue86 (PR #86)
don't require RELENGAPI_SETTINGS
shift messages around