Remove leading /bin/bash from systemd service ExecStart
Add user service
vimrc: Remove unnecessary makefile autocommand
vimrc: Use FileType for markdown settings
Install user session service as enabled

There's really no point in having it installed without having it
enabled.
Version 1.4.0

Changelog:
- Remove leading /bin/bash from ExecStart in systemd service definition
- Add service definition for systemd user session.  This will hook
  itself in when btsync.service starts in the user session. This service
  definition is installed directly to btsync.service.wants by the make
  script. If one wants to disable the service, one might as well
  uninstall the whole software.

Signed-off-by: Emil Lundberg <lundberg.emil@gmail.com>