New version v2.0.4

Changes since v2.0.3:

• openbsd/pkg_tools: Add (Thanks to Somasis)
• homebrew/Su*: Use --all flag when upgrading
• homebrew/*: Some typo fixes
• compile.sh: git becomes optional (useful for docker tester.)
• compile.sh: Get list of authors from README.md
• Makefile: Various improvements
• lib/00_core: Add _removing_is_dangerous method
• lib/00_core: _not_implemented now returns 1
• lib/help.txt: Remove list of authors from help message
• CHANGELOG.md: Add

v2.0.1

The first version 2.0.1 of the 2.0 branch