Fixes xuhdev#46

Run tex engine before and after bib executable
Add support for both `bibtex` and `biber`
 - Add global variable `g:livepreview_biber`
Add Bibliography section to README
 - Detail usage of `g:livepreview_biber`
 - Detail usage with `biblatex`

README.md

@@ -126,6 +126,26 @@ hold (autocmd events `CursorHold` and `CursorHoldI`), use the feature flag:
 let g:livepreview_cursorhold_recompile = 0
 ```
 
+### Bibliography executable
+
+`LLP` uses `bibtex` as the default executable to process `.bib` files. This can
+be overridden by setting the `g:livepreview_biber` variable.
+
+```vim
+let g:livepreview_biber = 1
+```
+
+Please note that the package `biblatex` can use both `bibtex` and the newer
+`biber`, but uses `biber` by default. To use `bibtex`, add `backend=bibtex`
+to your `biblatex` usepackage declaration.
+
+```
+\usepackage[backend=bibtex]{biblatex}
+```
+
+Please note that `biblatex` will NOT work straight out of the box, you will
+need to set either `g:livepreview_biber` or `backend=bibtex`, but not both.
+
 Known issues
 ------------
 

plugin/latexlivepreview.vim

@@ -184,14 +184,23 @@ EEOOFF
                         \ l:tmp_root_dir . '/' . bib_fn)                                " TODO: may fail if same bibfile names in different dirs
         endfor
 
+        if exists('g:livepreview_biber') && g:livepreview_biber > 0
+            let s:bibexec = 'biber *.bcf'
+        else
+            let s:bibexec = 'bibtex *.aux'
+        endif
+
         " Update compile command with bibliography
         let b:livepreview_buf_data['run_cmd'] =
                 \       'env ' .
                 \               'TEXMFOUTPUT=' . l:tmp_root_dir . ' ' .
                 \               'TEXINPUTS=' . l:tmp_root_dir
                 \                            . ':' . b:livepreview_buf_data['root_dir']
                 \                            . ': ' .
-                \       'bibtex ' . l:tmp_root_dir . '/*.aux' .
+                \ ' && ' .
+                \       b:livepreview_buf_data['run_cmd'] .
+                \ ' && ' .
+                \       'cd ' . l:tmp_root_dir . ' && ' . s:bibexec .
                 \ ' && ' .
                 \       b:livepreview_buf_data['run_cmd']