Replace `parseUrlpkg` from `@jspm/generator`

[JayaKrishnaNamburu]

The main reason for using this, is to create file names using packagename@version. So we use parseUrlPkg from the @jspm/generator. Again as i mentioned in #13 to keep the loader lean. Let's see if we can do the check in the loader itself.

Reason

• We are currently not bundling the loader along with it's dependencies and distributing to npm. So, that makes the users to download the whole @jspm/generator every-time they download the loader too. Give the use-case for extracting name and version, this is something we can avoid downloading.

[yowainwright]

I can re-add this?

[yowainwright]

I think, if I remember, this is done already as expected—to use parseUrlPkg.