\fret-diagram-verbose: use of capo not considered in fret-range

[Torsten Hämmerle]

> I'm not top posting.

% \fret-diagram-verbose with capo > 1 doesn't set minimum fret to
% capo fret so that capo will accidentally show up in the 1st fret.
%
% Preconditions:
% - capo > 1
% - all the place-fret values are <= fret-count (default: 4)
%
% REASON:
% fret-range will only be shifted iff maxfret < fret-count.
% Consequently, a capo in the 2nd fret will erroneously be
% displayed in the 1st fret, because fret-range begins with 1 
% and capo will be the lowest fret in the fret diagram.

% File: fret-diagrams.scm, function fret-parse-marking-list
% Original line of code:
%   (if (> maxfret my-fret-count)
% Proposed correction:
%   (if (or (> maxfret my-fret-count) (> capo-fret 1))

% Example:
% Dot on e string in the 4th fret (OK), 
% but capo in 1st fret (instead of 2nd fret)

\version "2.16.0"

\markup { 
      \fret-diagram-verbose #'(
        (capo 2)
        (place-fret 1 4))
}

% PS: this is my first bug report, so I do apologize for any inconvenience
% All the best
% Torsten