`jekyll` command prints a backtrace

[postmodern]

Users should never see a backtrace from a CLI program.

$ jekyll
       Deprecation: Jekyll now uses subcommands instead of just switches. Run `jekyll help' to find out more.
/home/hal/.gem/ruby/1.9.1/gems/commander-4.1.3/lib/commander/runner.rb:365:in `block in require_program': program version required (Commander::Runner::CommandError)
    from /home/hal/.gem/ruby/1.9.1/gems/commander-4.1.3/lib/commander/runner.rb:364:in `each'
    from /home/hal/.gem/ruby/1.9.1/gems/commander-4.1.3/lib/commander/runner.rb:364:in `require_program'
    from /home/hal/.gem/ruby/1.9.1/gems/commander-4.1.3/lib/commander/runner.rb:52:in `run!'
    from /home/hal/.gem/ruby/1.9.1/gems/commander-4.1.3/lib/commander/delegates.rb:11:in `run!'
    from /home/hal/.gem/ruby/1.9.1/gems/commander-4.1.3/lib/commander/import.rb:10:in `block in '

[parkr]

Users should never see a backtrace from a CLI program.

I hope you're kidding! Backtraces are incredibly helpful.

I agree that this could be cleaner, though.

[postmodern]

@parkr I am not kidding. Print a proper error message. Backtraces are only useful to developers, not users.

[parkr]

Jekyll is meant to be used by developers.

[parkr]

Now prints this:

~/code/jekyll/site$ bundle exec ../bin/jekyll --server
       Deprecation: Jekyll now uses subcommands instead of just switches. Run `jekyll help' to find out more.
       Deprecation: The --server command has been replaced by the 'serve' subcommand.
invalid option: --server