Moving to `grunt-assemble-i18n`

[doowb]

@LaurentGoderre we'd like to move this code to grunt-assemble-i18n and deprecating assemble-middleware-i18n on npm.

I noticed there are some outstanding issues and PRs that we can try to resolve before moving. There's also an issue for migrating to assemble@0.6.0. We can take a look at the code and see if there's any common code that we might want to extract from this module and create a common module that can be used in both libraries.

If you (or anyone else) have any issues/questions/comments, please leave them here and we can discuss.

[LaurentGoderre]

I'd say go for it!

[doowb]

Done. There wasn't a need to change any actual code (just some devDependencies that have be renamed too). We can open some other issues to extract code into common libraries and possibly make a new middleware/plugin for assemble 0.6.0.

• [x] tagged code snapshot before moving to grunt-assemble-i18n
• [x] renamed repo to grunt-assemble-i18n
• [x] updated code to use grunt-assemble and grunt-assemble-permalinks in tests