Introduce a TopologicalHash class

In the interest of `depends_on :cask`, we introduce a topologically
sortable hashmap, implemented as a small subclass of Hash.
Add exception for cyclic Cask dependencies
Implement Cask dependencies

as a class concerned with recursively loading, graphing and sorting all
dependencies of a given Cask.
Satisfy Cask dependencies on install

Includes an unsavory hack to bypass redundant checks for Cask
subdependencies, in the form of an optional argument passed down from
`install` to `satisfy_dependencies`.
Add tests for depends_on :cask
removed djay.rb

Only available to buy from the MAS
Improve uninstall stanza for d235j-xbox360-controller-driver

Explicitly unload kexts and launch service installed with the
driver. Manually delete symlink in /System/Library/Extensions
that is not removed elsewhere and causes a warning to be raised
if left after uninstall.
P4Merge 2014.2
Update uBar.app to v2.4.1

uBar v2.4.1 released 2014-12-29.
Update Cloak.app to v2.0.9
Merge pull request #8516 from sebnash/ubar

Update uBar.app to v2.4.1
Merge pull request #8517 from sebnash/cloak

Update Cloak.app to v2.0.9
Merge pull request #8491 from ndr-qef/core/depends_on-casks

Implement `depends_on :cask`
Merge pull request #8510 from vitorgalvao/remove-djay

removed djay.rb
Merge pull request #8486 from gpakosz/p4merge-2014.2

P4Merge 2014.2
Add Springy v1.6.1
Merge pull request #8501 from Dremora/springy

Add Springy v1.6.1
Merge pull request #8515 from jawshooah/d235j-xbox360-controller-driver

Improve uninstall stanza for d235j-xbox360-controller-driver
Update reaper to 4.76, add name, license and zap stanzas
Update mysqlworkbench to 6.2.4, add name, license and zap stanzas