Rewrite of enforce_ssl? and implementation of new options only_methods and except_methods.

[volontarian]

For "methods" a 3rd type of options I've rewritten the enforce_ssl? method to generate all condition variants of options from a keys_by_type hash (maybe the variable should be named options_by_type or matcher_options_by_type).

Now we should only need 1 test context with one pair of matcher option types and could remove all the other contexts testing all possible variants.

So I also have not written new test contexts for testing variants like only_method & only_host & only.

[rymai]

Thanks man,

I'll try to review this tomorrow but looks good from what I've seen!

[rymai]

Thanks, I've merged it.

It also give me motivation for refactoring the whole gem (see #33)! :)