Fix download protocol in OmniFocus.app Cask

Changed https to http because the former has stopped working
move require 'digest' to where it is actually used
dnscrypt uninstall: add :quit and correct :pkgutil
bug: `container_type :seven_zip` was ignored

because interior capitalization was not done
refactor GenericUnar container class

This is just a matter of semantics: renaming the abstract base
class `Cask::Container::UnarBase` so that it makes sense when
referring to it in a `container_type` stanza.
Merge pull request #5591 from rolandwalker/move_digest_require

move require 'digest' to where it is actually used
force permissions and delete ACLs if rmtree fails

This logic is ugly as the installation directory will be left
in a mangled state if it fails partway through.  However, the
same is true when `rmtree` fails partway through, which this
code is intended to minimize.

References: #5504
Use versioned URL for slack.rb
make platypus use a versioned URL and add appcast
rename messenger-for-telegram.rb to telegram.rb

Apparently upstream has changed the application name.

References: #5585
Merge pull request #5603 from rolandwalker/slack_versioned_url

Use versioned URL for slack.rb
Merge pull request #5605 from rolandwalker/telegram_rename

rename messenger-for-telegram.rb to telegram.rb
Merge pull request #5604 from rolandwalker/platypus_versioned_url

make platypus use a versioned URL and add appcast
Merge pull request #5599 from rolandwalker/generic_unar_container

refactor GenericUnar container class
Merge pull request #5598 from rolandwalker/allow_multiword_container_types

bug: `container_type :seven_zip` was ignored
Merge pull request #5597 from rolandwalker/dnscrypt_uninstall

dnscrypt uninstall: add :quit and correct :pkgutil
Merge pull request #5596 from rolandwalker/permissions_before_rmtree

force permissions and delete ACLs if `rmtree` fails
Add p4v.app v2014.1-888424
Merge pull request #5284 from blacksails/master

Fix download protocol in OmniFocus.app Cask
Merge pull request #5606 from disterics/p4v

Add p4v.app v2014.1-888424