Added rockspec and fixed naming inconsistencies

The build was different on arm vs x86_86 linux (`require 'LuaXml' on the former, `require 'LuaXML'` on the latter). The first commit fixes that issue.

There were also tons of extra carriage returns in the repo, which I also fixed. I believe `git` will convert the line endings appropriately if there are no carriage-returns to begin with.

The final commit adds a rockspec. If you decide to pull this, then change the `url` in the rockspec to be this repository instead of my fork. When adding the rockspec, I updated the version number in the rockspec to be 1.7.5 (one more than on the webpage).

Also, the repository's url 404s for me. This url (`homepage` in the rockspec), however, works: http://viremo.eludi.net/LuaXML