Particularly, the Makefile would try to build propellor if there were
updates, but if this build failed because a bad commit was pushed, it would
abort w/o pulling any new fixed commits.
Anyway, it's better to move away from using the makefile when possible as
it's just for bootstrapping, and also I would like to make "make" not
default to running propellor as that can be confusing behavior.
(I can't change that yet; needed for upgrades. Should be fine to change
after several more releases, or maybe a year..)
This is to work around OSX's brain-damange regarding filename case
insensitivity.
Avoided moving config.hs, because it's a config file. Put in a symlink to
make build work.