Taps should be managed case-insensitively

[zbentley]

If I have a manifest that does:

package { "Caskroom/versions":
    ensure   => present,
    provider => tap,
}

The tap will be installed successfully (i.e. homebrew can use packages from it), but Puppet will continually notify about reinstallation of the tap on every run.

This is because the tap's canonical name is caskroom/versions (lower case C), but the brew tap command operates case-insensitively.

The presence-or-absence detection used by this module should be case insensitive on taps--and probably on all Homebrew objects/operands that are handled case-insensitively by Homebrew, which I think is many/most things.