explicit UTF-8 encoding for old Rubies

This does no harm, and was sufficient to make the following
command pass on my development machine:
    ruby1.9 /usr/bin/rake test
Add a cask for cert-quicklook plugin
make order consistent across Ruby vsns w/sort

Fixes #2635.  In particular, link and cookie order differ
between Ruby 1.8.7 and 2.x, causing the test suite to fail
under 1.8.7.
add `before_install` and `before_uninstall`
Add callnote v2.3.7
add Cask::SubversionDownloadStrategy

abstract out module `Cask::DownloadStrategy`, add some commentary
add command `brew cask cleanup`

plus new option --outdated
Show managed links in "brew cask list"

Fixes #2261
don't choke when :args is not present

in _process_options
allow command.run without arguments

ie only an exectuable
test valid keys in _process_options

add monkeypatch on Hash in utils.rb for `assert_valid_keys` method
Upgrade tor-browser to 3.5.2
Merge pull request #2856 from joelpurra/tor-browser-3.5.2

Upgrade tor-browser to 3.5.2
Add thong v1.1
Merge pull request #2857 from jk/feature/thong

Add thong v1.1
Merge pull request #2759 from rolandwalker/cleanup_cmd

add command `brew cask cleanup`
RStudio v0.98.501
Merge pull request #2851 from rolandwalker/system_command_followups

System command followups
Merge pull request #2858 from aaronwolen/master

RStudio v0.98.501
Update Light Table to 0.6.3