Use ruby-mode for Podfile

A Podfile is used for CocoaPods to do a Bundler like dependency
management in XCode projects. Similar to a Rakefile or a Gemfile the
Podfile contains a dependency description in a Ruby based DSL.
Merge pull request #473 from jehrhardt/podfiles

Use ruby-mode for Podfile
Factor the search engine installation to ease the future install of new ones.
Add DuckDuckGo search engine in the default list.
Add binding `C-c U` for DuckDuckGo search
Merge pull request #476 from ardumont/add-duckduckgo-search-engine

Add DuckDuckGo to the search engines list
web-mode is now compatible with minor modes
Merge pull request #485 from bixuanzju/patch-1

web-mode is now compatible with minor modes
[Fix #484] Set OS X specific latex settings conditionally
FIX: `coffee-mode` uses `coffee-tab-width` instead of `tab-width`.

And recently it has removed `tab-width` dependency completely.
Merge pull request #493 from pokehanai/hotfix/coffee-tabwidth

FIX: `coffee-mode` uses `coffee-tab-width` instead of `tab-width`.
Don't mess with Projectile's modeline text
Merge branch 'master' of github.com:bbatsov/prelude
Attempt to refactor two "duplicate" functions.

Attempt to extract a generic function `prelude-get-positions-of-line-or-region` from `prelude-duplicate-current-line-or-region` and `prelude-duplicate-and-comment-current-line-or-region`
Merge pull request #499 from bixuanzju/patch-1

Attempt to refactor two "duplicate" functions.
don't enable coffee-cos mode if buffer filename is nil
Merge pull request #501 from wishbear/master

don't enable coffee-cos mode if buffer filename is nil
Open files with .cl extension in lisp-mode

I'm surprised that this isn't already the case.

Although most people use the .lisp extension, some do use .cl
Correct terminator for .sbclrc
Open .podspec files in Ruby mode

.podspec files use a Ruby DSL for the CocoaPod dependency management
system, common in iOS development.

Although the Podspec file correctly opens in Ruby mode, the .podspec
file does not. This corrects that.