Allow for non-root target directory

[s0]

There have been a number of requests around pushing to sub-directories of target branches, rather than the root. This is possible with a custom CLEAR_GLOBS_FILE file, and by replicating the structure of the target directory, but this usage could be significantly simplified.

(e.g. #64, #65, etc...)

[jdcmarques]

Hey, just opened a PR with an implementation for this, can you take a look?

#82