Add new colormap for attachment sybol with sane fallback for existing colorschemes.

Squashed commit of the following:

commit 8dcf98df8e9104a5dc75539f64512cc91ed7eeba
Author: madhat2r <MaDhAt2r@dukefoo.com>
Date:   Wed Apr 23 08:48:29 2014 -0500

    Add new colormap for attachment sybol with sane fallback for existing
    colorschemes.

commit 78007ef68d55d79b5f8209cdc23a9644808a3962
Author: madhat2r <MaDhAt2r@dukefoo.com>
Date:   Tue Apr 22 18:54:14 2014 -0500

    Add new colormap for attachment symbol

commit 2a5b5d686271e0d21c3a9480cdfb5cc4ee54997e
Author: madhat2r <MaDhAt2r@dukefoo.com>
Date:   Tue Apr 22 15:43:43 2014 -0500

    Add optional colormap for attachement symbol
history: new :with_attachment