lib: expose argument `?additional_commands`
test: use `additional_commands` in `run_main` example
doc: update documentation with `?additional_commands`
lib: fix minor display bug in the Explorer
Merge pull request #8 from hammerlab/fix_display_bug

lib: fix minor display bug in the Explorer
Merge pull request #7 from hammerlab/expose_additional_commands

Expose additional commands