added MacOS-compatible hook for tab completion, but the tab completion
routine as written is not compatible with it, so needs work
Merge branch 'master' into mac_tab_completion
pulling in some new features that need autocompletion
using different code from the SO, and tweaking it a bit, seems to have made
this work on the mac (#23), need to test on Linux
having to special-case how pathnames are handled in completion routine #23
for libedit vs readline
Merge pull request #24 from joefutrelle/mac_tab_completion

Mac tab completion