Rename internal notmuch_rb variables

Now we are the official one.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Rename public notmuch_rb variables

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Move default sets to set_defaults()

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Add wrapper for old variable names

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Fix search shortcut

So that it can receive multiple arguments.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Rename to notmuch.vim

And update documentation do deemphasize the Ruby aspect.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Add vim help

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Document direct search

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>