Get \cite{} and \ref{} completions from open buffers

[Aligorith]

When there is no texroot stuff defined, it would be good if the \cite{} and \ref{} commands would just look for the relevant labels in the open buffers (i.e. any .bib files open in the current window/session for \cite{], and any .tex files for \ref{}), instead of just popping up the annoying "No bib files found" error or not allowing any completions at all.

I'm currently working my thesis and have a complicated multi-folder setup that I'm compiling out of Sublime via a batch script.

[Aligorith]

I originally opened this as a feature request, but quickly found that it was much easier than I expected to be able to quickly patch this. Now happily using this fix locally :D