plugin: Inline ruby commands that fits on one line
plugin/s:show(): The buffer is modifiable at creation time
bufferlist: initial support
Merge branch 'master' into list_buffers

* master:
  database-v1: initial import
Merge branch 'master' into list_buffers

* master:
  main: extract the code rendering a thread line into it's own method
  uranusmail: move the date_format to the config section in .notmuch-config

Conflicts:
	plugin/uranusmail.vim
thread: for each thread create a MailThread to query it directly
buffer_list: show the thread info for a buffer
buffer_list: fix a failing spec on CI
buffer_list: Do not kill the search buffer, instead show and refresh an existing one

This fixes the bug reproduced by these steps:
- Open Uranusmail
- Open a folder
- Open a message
- Show the list of buffers
- Show the folder
- Open a different message
- Show the list of buffers
- Select the last buffer
- The loaded buffer should be empty and keybinding do not work
search: Set the default date US format
fix failing specs on CI
Merge pull request #1 from uranusmail/list_buffers

List buffers