multiline: welcome
refactor part 1

moved a lot of stuff around, into their own files.  wrote a lot of tests.
remove pkg, needs to be proper assertion
more extracting
assertions helpers extracted
replace multiline with bag
move destinations to bag
everything in its right place
bake: now just an eval
ok: better status messages
tests get fixtures
migrate apt to new format
migrate brew to new format
remove `fixtures` test helper, use $fixture

...in the spirit of keeping things simple, and avoiding gotchas with multiline
stings and quoting variable names
migrate directories to new format
migrate symlinks to new bake
migrate git to bake
mocks now using respond_to
Merge branch 'refactor/status_uses_bake'
assert group: initial port