Support dynamic configs like in boot for migrations et al
Add support to lein caribou that allows the user to specify either :boot or :static as a way
to support both dynamic "boot" configs and the static edn in config files. To use the keyword
optoins, the user supplies the keyword where the config argument would have gone in the lein
task and then either a file or function to load the config from. For example, to run migrations
on a dynamicly generated config file, the user would input

'lein caribou migrate :boot project-namespace.boot/boot-config'

and the config map from that function would be retrieved. Supporting this requires also modifying
run-migrations in caribou-core to accept a config map instead of a config file. I have submitted
a pull request there already in a branch called migrations-from-boot.
Modified so that each config loading function passes its own namespaces and a callback
Previous commit had the :boot option trying to read the config by running eval-in-project. The issue
there is that eval-in-project runs in a subprocess and so will not return anythin. This modification
makes each loading function pass its namespace and a callback so that the main eval-in-project
being run to do migrations, rollbacks, or catapult can grab the config file in that single process.
Bracket typo
version
Merge branch 'boot-config-support' of github.com:abpoms/lein-caribou into abpoms-boot-config-support
Namespace functions properly and don't create anon function until inside the project jvm subprocess
Merge branch 'boot-config-support' of github.com:abpoms/lein-caribou into abpoms-boot-config-support