Added rudimentary support for BibLaTeX

[BibLaTeX](http://www.ctan.org/pkg/biblatex), the successor of BibTeX, uses `\addbibresource` instead of `\bibliography` to specify paths to `.bib` files. This commit enables users to get autocompletion for citing.
Merge pull request #11 from tlycken/biblatex

Added rudimentary support for BibLaTeX