Update bindings.cc

double include "lua.h"
  Bugfix:  There might not be a single folder.

  I'd always assumed there would be a valid list of folders beneath
 the maildir_prefix.  Mostly because what's the point of running a
 maildclient, or trying a new one, if you have no mail?!

 Anyway if ~/Maildir, or whatever valid `maildir_prefix` is configured
 to point to a directory which is empty we'd segfault on trying to open
 or toggle a folder.

  Fix this by returning if the maildir.size is zero.

  This is not a complete fix because the maildir mode should draw
 a string of the form:  "no valid maildirs found".

  Closes #9.
Merge pull request #8 from 7histle/patch-1

double include "lua.h" // just noticed
  Fixed broken link markup
  Implement the on_read_message hook.

  When a message is displayed call out to the user-supplied
 on_read_message hook.
cleanup

cleanup for pull request #8
Merge pull request #10 from 7histle/patch-2

cleanup
  Added current_message().

  This is part of issue #11.
  Added new primitive is_new().

  This will return 1/0 depending on whether the currently selected
 message is new.  If you prefer you may pass a message-path.

  This updates Issue #11.
  Updated so that is_new( path ) works.

  I'd neglected to implement half the functionality.
  Added: mark_new() + mark_read();

  This updates issue 11.
  We don't mark a message as read when viewing it.

  This separates the "view" from "mark read" behaviour, and
 defers to Lua where policies can be set.
  Added count_messages().

  This returns the number of messages in the currently
 selected folder(s).
  Three new primitives:

   * jump_maildir_to
   * jump_index_to
        * Jump to the given offset in the lists.
   * count_maildirs()

  New keybinding "*" to jump to the end of the lists.
  Formatting updates.
  Formatting updates.

  four-space indents
  Mention the coding style.
  Added new function - mark_all_read()

  This is a useful utility, not bound to a key.