Merge pull request #49 from lyokha/master

wrap_args() must check that arg contains '='
formatting: make custom indentexpr optional.
toc: handle some cases that caused errors

check if there is a valid locationlist, if there is a filename, prevent
some error messages
created `chdir` module.

Automatically change the window current directory to the one the current
file is in.
python/command: fallback to sync method if v:servername is null

sometimes, console vim doesn't register a servername, which caused the
Pandoc command to send invalid arguments to async.py.
command: implement command templates system.

also, reorganized menu
Merge branch 'master' of github.com:vim-pandoc/vim-pandoc
chdir: fix for the case where the buffer has no name
command: allow customization of the command that opens the created files.

Closes issue #50.
keyboard: improve creation of reference definitions

always move after the current paragraph, and keep selection.
bib: couple fixes

* make extensions of bibliographies to search for configurable.
- json bibliographies no longer read by default.
* don't try to load data from invalid json files.

should fix or improve issue #55.
g:pandoc#biblio#bib_extensions applies only to b and c flags of g:pandoc#bib#sources

fixes issue #55.
folding: make markdown detection more lax

should enable loading our rules for vim-rmarkdown handled files, which
have `rmarkdown` filetype.
folding: allow initial foldlevel to be configurable.
bibliographies: bibtex extension was wrong
bibliographies: make vim-pandoc aware of new bibliographies types.
Minor documentation fixes.
Merge pull request #59 from memeplex/master

Minor documentation fixes.
don't treat rustAttribute as a fold marker

rustAttribute from the official Rust vim plugins
general: apply consistent indentation to files

thanks to @memeplex.

Script used:

    #!/bin/bash

    modeline='" vim: set fdm=marker et ts=4 sw=4 sts=4:'

    find . -name '*.vim' | while read script; do
        [[ $(head -1 "$script") == '" vim:'* ]] || \
            sed -ir '1s/^/'"$modeline"'\n\n/' "$script"
        sed -ir -e '1s/^" vim:.*$/'"$modeline"'/' \
            -e 's/\s$//' \
            -e 's/\t/        /' \
        "$script"
    done