change head.load api to pass attributes to loaded dom element

[jaypea]

As mentioned in #312 I would like to load a CSS file with media="print" attribute.
This PR is inspired by @robert-hoffmann comments in #262 (comment) and in #267 (comment)

It is now possible to add options to an asset. Implemented are additional attributes to the created DOM elements (link or script).

head.load({
           mylabel: "somescriptPath",
            options: {
                attributes: {
                    "data-main": "loaded1"
                }
            }
        },
       callback
);

I could not find any script to create the dist files, is there one?

[jaypea]

btw, travis fails because this is a pull request from a fork and travis encrypted env variables do not support this. travis fails on grunt settting up saucelabs and never gets to test any code.

[robert-hoffmann]

Nice hack man !

I can't diff it in right now cause i need to setup my dev environment again, but i'll definitely have a look and see if there are no hidden catches in there. Igorlima did some nice changes a while back https://github.com/headjs/headjs/pull/215/files but i think i rolled them back cause something was going wrong, and code seems very similar ..i'll just have to do all the unit tests ;-)

Minification/bundling is not automatic, i do it manually (well my dev environment does it..) before checking in the code. Gonna have to automate that with grunt ..maybe uglify.

[APlusDesign]

This definitely needs action, I mean I have to use crap like this to include a print a style sheet with head.js currently, I shiver every time I see it...

head.ready("jquery", function() {
    head.ready("print_css", function() {
        $('link[href="/pathtofile/print.min.css"]').attr('media','print');
    });
});

[jaypea]

closing this after 2 years.