added g:openbrowser_short_message
Merge pull request #27 from basyura/short_message

added g:openbrowser_short_message
fix #28: some <Plug> mappings won't work

* <Plug>(openbrowser-search)
* <Plug>(openbrowser-smart-search)
uses s:get_url_on_cursor(), but it could use expand('<cword>')
instead of URL under cursor
fix doc: <Plug>(openbrowser-open)
add s:warn() for WarningMsg
error message on <Plug> mappings
 vitalize for vital's critical bug (ref vim-jp/vital.vim#100)
s:Process.system_bg() was renamed (thanks @basyura)

37717cb causes an error:

    E716: Key not present in Dictionary: system_bg

because s:Process.system_bg() was renamed to s:Process.spawn().

thanks @basyura for bug report.
https://github.com/tyru/open-browser.vim/commit/37717cb49b0cfaa05fa9c16a5c3759ca5e3ebdf2#commitcomment-3884304
use :redraw! instead of :redraw (ref #29)
Merge branch 'redraw-bang' (close #29)
vitalize (follow Process module change)
urilib: don't escape each path
fix #30: escape cmdline-special items

* specify 1 to {special} argument of `s:Process.spawn()`
* change g:openbrowser_browser_commands default value
fix #31: don't shellescape() in g:openbrowser_browser_commands

Vital.Process.spawn({list}) also does shellescape().
so the arguments are shellescape()d twice.
remove unnecessary comment
remove unused function openbrowser#shellescape()

I haven't written this autoload function to help yet.
so it should be safe to remove it.
use Vital.Web.URI instead of urilib
remove urilib.vim and its related files
Merge branch 'vital-web-uri'
use Vital.Web.HTTP.encodeURIComponent() for query

urilib.vim did URL-encode before
but the feature was removed at fa5fca4335.