Add Fender Amp Drivers Cask.
Add Fender FUSE Cask.
Merge pull request #1235 from gillesfabio/add-fender-amp-drivers-cask

Add Fender Amp Drivers Cask.
Merge pull request #1236 from gillesfabio/add-fender-fuse-cask

Add Fender FUSE Cask.
Add NetShade cask

Adds a cask for NetShade, an anonymous proxy management tool.
Add Mono Framework MRE (Runtime) Cask.
Add Mono Framework MDK (SDK) Cask.
Merge pull request #1241 from gillesfabio/add-mono-mre-cask

Add Mono Framework MRE (Runtime) Cask.
Merge pull request #1242 from gillesfabio/add-mono-mdk-cask

Add Mono Framework MDK (SDK) Cask.
Add Xamarin Studio (MonoDevelop) Cask.
Merge pull request #1243 from passelin/netshade

Add NetShade cask
Merge pull request #1244 from gillesfabio/add-xamarin-studio-cask

Add Xamarin Studio (MonoDevelop) Cask.
Add Akai LPK25 Keyboard Editor Cask.
Add new cask for Prey project.

This cask install the batch version of Prey package, as detailed in:
http://support.preyproject.com/kb/installation/how-to-deploy-prey-in-batch-mode-mac-os

As it requires an API key to be installed, a warning is displayed to the
user with an explanation on how to fix the issue.

Also added -E option to sudo invocation so environment variables can be
passed to the installer.

closes #953

Signed-off-by: phinze <paul.t.hinze@gmail.com>
Merge pull request #1245 from gillesfabio/add-akai-lpk25-editor-cask

Add Akai LPK25 Keyboard Editor Cask.
Add a cask for Balsamiq Mockups

Adds a cask for Balsamiq Mockups, a rapid wireframing tool.
Merge pull request #1246 from passelin/balsamiq-mockups

Add a cask for Balsamiq Mockups
require most commands to succeed; cleanup on install failure

- add `run!` method which raises if command does not succeed
- use `run!` when the command we are running must succeed for things to
  move forward. this should help produce clearer error messages in
  failure scenarios.
- move caveats earlier in the install process so reports can be made
  about potential failures
- remove the destination tree on cask install failure, so the cask will
  not be considered installed
Merge pull request #1247 from phinze/dev/commands-must-succeed

require most commands to succeed; cleanup on install failure
cut v0.19.1