Update README.md

Added missing sudo for mac installations.
Fix issue with linux_admin dependency.
Fix issues with gem spec.

Remove doubling of summary and description.
Fix homepage URL.
Add Jason Frey to authors.
Merge pull request #6 from Fryguy/fix_issue_with_gemspec

Fix issue with gemspec
Release v0.4.1
Upgrade to linux_admin v0.5.7 to loosen active_support dependency.

Change .travis.yml to remove support for 1.9.2
Merge pull request #7 from Fryguy/loosen_dependency

Upgrade to linux_admin v0.5.7 to loosen active_support dependency.
Release v0.4.2