Fix typo: "loopping" --> "looping"
Don't have Travis try to build with 4.02.0

Fixes #47
lib: fix error messages for `check-process`
Merge PR #27
Merge PR #29
lib: fix escaping in Command_line.inspect

This is from my own comment in PR #30.
Fix typo
lib: fix whitespace & comments (PR #33)
Merge PR #33
lib: fix typo in plugins documentation (PR #34)
Merge PR #34
Merge PR #35
lib: do cosmetic changes (PR #48 & #30)
Merge PR #48
doc: remove annoying whitespace (#45)
Merge PR #45