Determine the Homebrew owner from enviroment variables & node attrs.

Homebrew installation and package commands will be run under a user
determined using the following rules (first match wins):

1. If node['homebrew']['owner'] is set, use this user
2. If ENV['SUDO_USER'] is present, Chef was invoked with sudo so
   use the original non-privileged user
3. Raise and exception if the calculated user is 'root'
4. Otherwise default to current user, taken from ENV['USER']
Add documentation for node['homebrew']['owner'].
Scope File to ::File, even inside not_if/only_if, for consistency.
Merge pull request #17 from fnichol/non-root-and-sudo-support

[COOK-3283] Determine the Homebrew owner from enviroment variables & node attrs.
Update CHANGELOG format
Add license headers and fix README format
Version bump to v1.4.0
Bump devodd release
[COOK-3589] Set homebrew as the default package manager on OS X Server

Signed-off-by: Seth Vargo <sethvargo@gmail.com>
Version bump to v1.5.0
Version bump to v1.5.1
[COOK-3825] homebrew_package needs /Users/someara set

Signed-off-by: Sean OMeara <someara@opscode.com>
Version bump to v1.5.2
Version bump to v1.5.3
[COOK-4023] Fix installer scripts URL

Signed-off-by: Sean OMeara <someara@opscode.com>
Fixing up rubocops.
Version bump to v1.5.4
Version bump to v1.5.5
[COOK-3960] Added LWRP for brew cask

Signed-off-by: Sean OMeara <someara@opscode.com>
[COOK-4508] Add ChefSpec matchers for homebrew_tap

Signed-off-by: Sean OMeara <someara@opscode.com>