https://github.com/mpeterv/luacheck/pull/81#issuecomment-261099606
> If you really want to use bleeding-edge version you should get the
> rockspec from master branch, not a fixed commit ...
> The correct way to install from a specific commit is cloning that
> commit and running "luarocks make" from project directory. The reason
> is that running "install" or "build" on an scm rockspec fetches
> sources from master but uses build description from the rockspec
> itself, which may be outdated.
Check `exists('b:term_title')` to avoid the BufReadCmd for already-initialized
:terminal buffers.
Move the test for `:argadd`.
Add a test for `:edit<CR>`.
Tweak comments and code style.
