Recast Cask::DSL::Installed as Cask::Staged

Change namespace for clarity, as we already have Cask::Installer,
and are about to add Cask::DSL::Installer.

Move to parent because these methods are not DSL-specific.
use path_environment_variable for caveats test

instead of manual_installer
recast install_script to installer :script

* document installer :script.  install_script was never documented
doc: remove needless column from table
dsl: add `installer :manual`

a toplevel artifact, intended to replace `manual_installer`,
which is currently implemented within the `caveats` mini-DSL
downgrade j.rb to version 802

per http://www.jsoftware.com/stable.htm, version 803 is a beta,
which may explain why the binary was changing, breaking the checksum.
update librecad.rb to 2.0.5

* provide mountain lion-specific download
* update license to :gpl
Fix checksum in Pharo.app Cask
document `appcast` stanza

The :latest_version key stays undocumented, as it is not
clear yet whether it is useful
Upgrade Oracle Java to 1.8u25
Merge pull request #6681 from bfanger/java

Upgrade Oracle Java to 1.8u25
Merge pull request #6679 from Zi0P4tch0/pharo-cask-fix

Fix checksum in Pharo.app Cask
appcast :format in epub-to-pdf
appcast :format in xamarin-android
appcast :format in xamarin-ios
appcast :format in xamarin-studio
Merge pull request #6677 from rolandwalker/j_downgrade

downgrade j.rb to version 802
Merge pull request #6678 from rolandwalker/librecad_2.0.5

update librecad.rb to 2.0.5
Adds multipatch cask v1.4

Multipatch can be used to apply IPS patches, among other things.
Merge pull request #6685 from vitorgalvao/fix-6684

Adds multipatch cask v1.4