convert couleurs.rb to `depends_on :macos`

from caveats `os_version_only`.
convert deeper.rb to `depends_on :macos`

from caveats `os_version_only`.

Also tweak unrelated version-specific caveat.
convert maintenance.rb to `depends_on :macos`

from caveats `os_version_only`.

Also tweak unrelated version-specific caveat.
convert fenics.rb to `depends_on :macos`

from caveats `os_version_only`.
convert tunnelblick.rb to `depends_on :macos`

from caveats `os_version_only`.
convert ubar.rb to `depends_on :macos`

from caveats `os_version_only`.
convert zooom.rb to `depends_on :macos`

from caveats `os_version_only`.
Upgrade synergy to 1.6.2
Update sloth license from unknown to gpl

http://sveinbjorn.org/sloth
Update rstudio license from unknown to affero

see https://github.com/rstudio/rstudio/blob/master/COPYING
Update r license from unknown to gpl

See https://svn.r-project.org/R/trunk/doc/COPYING and https://svn.r-project.org/R/trunk/doc/COPYRIGHTS
Update multibit license from unknown to mit

See https://multibit.org/
Update controlplane license from unknown to gpl

See https://github.com/dustinrue/ControlPlane/blob/master/COPYING.txt
Update colloquy license from unknown to gpl

See http://colloquy.info/project/wiki/Source%20Code
Update cocktail license from unknown to commercial

Trial expires after tenth launch
Update cleanmymac license from unknown to commercial

Limits cleaning until purchase
Update libreoffice license from unknown to oss

Licensed under mpl but includes software with many licenses, including gpl
Merge pull request #7792 from Amorymeltzer/update-licenses

Update licenses for a few casks
Merge pull request #7789 from vitorgalvao/fix-7787

Upgrade synergy to 1.6.2
DSL: `depends_on :arch` functionality/tests/doc

* fill in functionality for the `depends_on :arch` stub
* de-document `caveats` method `arch_only`