* The information extracted from Homebrew's JSON command now also
includes information about linked keg and installations.
* The mapped versions in the App class now contain information about
the Homebrew installation as well.
* A HomebrewDiagnostics class has been added, which is currently able
to detect conflicts between the `php` formulae of core and the
`shivammathur/php` tap (which is currently an issue, see #54)
* Alerts are now displayed as critical if they are truly problematic.
* PhpInstallation was renamed to ActivePhpInstallation, to make room
for a generic PhpInstallation object which contains cached info.
* Shell.pipe() now returns the contents of standardError if
standardOutput was empty and there was some data in standardError.
This makes it easier to debug the output of commands that output to
standardError. (For example, failed brew commands might.)
