Deprecated filename component.json

When using bower >=0.9, the package metadata file should be called `bower.json`, instead of `component.json`. Running `lein bower install` with bower 1.2.8 generates this deprecation warning:

    bower                       deprecated You are using the deprecated component.json file

I'd recommend just switching references of "component.json" to "bower.json" in `bower.clj`, as bower <0.9 is relatively old.

If lein-bower should support legacy versions too, perhaps it can be configurable in `project.clj`? This is what I proposed in bodil/lein-npm#2 when bower functionality was there, allowing `:bower-file "component.json"` to override the default filename of `bower.json`.

Thoughts?