Make fixes

[martindurant]

Fixes #163
Fixes #164

@sgdecker note usage for the list of paths (which became test_gh165):
each element of the input list can be

• single string, which means descend to the child catalogue
• a list of paths which means merge using these entries (can only be last element)
• a glob string (* and ? only), which means do string matching. We also allow passing a single string rather than a list, if doing one-level of glob only.