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.
Merge pull request #505 from Abizern/clisp-extension

Clisp extension
Merge pull request #506 from Abizern/podspec

Open .podspec files in Ruby mode
Merge remote-tracking branch 'bbatsov/master' into bbatsov-master