Update "Differences to Foreman"

It would have been helpful to me to have a better sense of Honcho's relationship to Foreman before wading into the project. This commit works the comment at https://github.com/nickstenning/honcho/issues/55#issuecomment-34163304 into the "Differences to Foreman" section of the documentation.
Merge branch 'patch-1' of git://github.com/whit537/honcho into issue_58
use proper language
syntax errors for python3
Merge branch 'lint_fixes' into fix_issue_61