Allow to specify filetype depending on file name, not only by extension

Now you can specify `:filenames` option in your behaviors file to assign file type depending on file name, not only by extension.

For example here I ask to highlight `Gemfile` and other files as ruby code:
```clojure
:files [(:lt.objs.files/file-types [{:name "Ruby"
                                     :filenames ["Gemfile" "Rakefile" "config.ru" "Capfile" "Guardfile"]
                                     :exts [:rake]
                                     :mime "text/x-ruby"
                                     :tags [:editor.ruby]}])]
```

Please look at code, I can't name myself as a Clojure programmer; so maybe pull-requested code is not so idiomatic.