Make this available in the package archive melpa as well.

Hi, I wanted to get this package added to melpa (an alternative to el-get) and submitted a recipe.  As part of this process [it was suggested that css-eldoc shouldn't start itself automagically](https://github.com/milkypostman/melpa/pull/981#issuecomment-23213033).  Hopefully these minor changes are welcome.

It might also interest you that auto-complete already has a built-in list of CSS keywords, with automatic narrowing to the allowable values, through the `ac-source-css-property`.  You might consider using this completion source instead of your custom dictionary.

Any plans on adding the missing css3 properties?