candidate_version relies on an awk expression that now works with brew 0.9.2

candidate_version parses the output of brew info with a regex incorporating a whitespace.

awk assumes that brew info will format output as

> tmux stable 1.6, HEAD

However, brew 0.9.2 formats as

> tmux: stable 1.6, HEAD

The old awk regex couldn't pick up the 0.9.2 formatting and would always no available packages.

New awk regex is sensitive to both whitespace and colon formatted info.
Provider requires the attribute ['homebrew']['run_as'] to be present

install silently fails with brew if you run as root, so we need to nominate a non-root user to install packages a
Merge branch 'master' of github.com:Govan/homebrew

Conflicts:
	libraries/homebrew_package.rb