Remove homebrew-fork Checksum class and refactor

* perform actual checksum calculation within download.rb
* use an accessor named sha256 instead of sums for checksum data
* migrate checksum-specific exceptions out of homebrew-fork
remove homebrew-fork extend/string.rb

Integrate the last remaining monkeypatch `undent` into our own codebase.
Upgrade Wesnoth.App to 1.12
Merge pull request #8392 from rolandwalker/remove_homebrew_extend_string

remove homebrew-fork extend/string.rb
Merge pull request #8388 from rolandwalker/remove_homebrew_checksum

Remove homebrew-fork `Checksum` class and refactor
remove homebrew-fork class Tty

* migrate into our codebase at lib/cask/utils/tty.rb
* merge with our monkeypatch
rm some unused methods from homebrew-fork mac.rb
whitespace
strip more unused methods from extend/pathname.rb

in homebrew-fork
Merge pull request #8390 from rolandwalker/remove_homebrew_tty

remove homebrew-fork class `Tty`
Merge pull request #8393 from rolandwalker/remove_homebrew_mac_methods

remove some unused methods from homebrew-fork `os/mac.rb`
Merge pull request #8391 from rolandwalker/remove_unused_pathname_methods

strip more unused methods from homebrew-fork extend/pathname.rb
Rename XBMC to Kodi and amend homepage/license
Merge pull request #8387 from von-forks/wesnoth-1-12

Upgrade Wesnoth.App to 1.12
Update uBar to v2.4.0

uBar v2.4.0 released 2014-12-20.
Merge pull request #8400 from sebnash/ubar

Update uBar to v2.4.0
adventure.rb: simplified homepage
alarm-clock.rb: simplified homepage
alinof-timer.rb: simplified homepage
android-studio.rb: simplified homepage