Fix download protocol in OmniFocus.app Cask

Changed https to http because the former has stopped working
Add DoubleCommand v1.7
Add iSwiff cask

iSwiff is SWF Player.
Give users hint that pkg installs work differently

Users should not have to open the Cask file to figure out why one
cask installs differently than another.

Closes #5402.
Add Google Nik Collection
Add Kensington TrackballWorks for Mac 1.1.2
Add TextSoap.app
Upgrade x2goclient to latest
Add Espionage.app latest
Delete special files (eg symlinks) from pkg BOMs

`pkgutil --only-files` plus `pkgutil --only-dirs` does not
cover all files in the BOM.

Closes #5491
Add Sony Homestream v1.1 cask
Fix markdown link in CONTRIBUTING.md

Added a missing closing parentheses.
Merge pull request #5557 from fapper/patch-1

Fix markdown link in CONTRIBUTING.md
Upgrade Geppetto.app to v4.2.0
Update FileZilla.app to v3.9.0.1
Upgrade LyX to v2.1.1
Merge pull request #5548 from rolandwalker/notify_pkg_install

Give users hint that pkg installs work differently
Merge pull request #5559 from mtneug/filezilla

Update FileZilla.app to v3.9.0.1
sha256 is :no_check, version is 'latest'
Upgrade PyCharm.app to v3.4.1