browserify as peer dependency
Fix crash on karma config without browserify property

Fixes this error:

    node_modules/karma-browserify/lib/index.js:148
        extensions: config.extension,
                      ^
    TypeError: Cannot read property 'extension' of undefined
        at configuredBrowserify

If your karma config module doesn't have a "browserify" property at all.

Uses mostly coffeescript function argument default value syntax
Updates and cleans up package.json.

Also, changes version to 0.5 so that the package feels more mature.
Adds badges and license to README.md
Merge commit '1d4e7d5444567ba95d6353276addb29ad425bd0a'
Merge commit 'b1b33a5bbd11b38e03ffd7c6ffdbdd7bba86840d'